WASHINGTON
HOP
COMMISSION
."^S
%
1994 REPORTS
and
1995 PROPOSALS
IRRIGATED AGRICULTURE RESEARCH AND EXTENSION CENTER
College of Agriculture and Home Economics
Washington State University
Prosser, WA
Preliminary Report Not for Publication1
December 1994
Contents
Control of Insects and Mites on Hops
W. W. Cone
Page
1
Hop Diseases and Their Control
R. E. Klein
Page 18
Water Management and Chemigation of Subsurface Irrigated Hops
R. G. Evans
Page 28
Weed Control in Hops
R. Parker
Page 31
Assessment of the Effects of Current Hop Yard
Management on N Cycling Relative to Water Quality
R. G. Stevens
Page 38
Hop Cultivar Development, Physiology and Chemistry
S. T. Kenny
1
Page 45
This is a progress reportof cooperativeinvestigations containing data interpretations which
may be modified with additional experimentation. Mention of a product or cultivar name
is for benefit of the reader and does not imply endorsement by Washington State University
or the United States Department of Agriculture.
PROJECT:
4380
TITLE:
Control of Insects and Mites on Hops
PERSONNEL:
W.W. Cone, Entomologist, WSU-Prosser
L.C. Wright, Research Tech Supervisor, WSU-Prosser
A.J. Perez, Farm Equipment Operator II, WSU-Prosser
M.M. Conant, Research Tech I, WSU-Prosser
OBJECTIVES:
1.
Continue to screen and evaluate new compounds or combinations as they become
available. Provide samples for chemical residue analyses and pursue registration for the
most promising compounds.
2.
Develop a procedure for measuring pesticide resistance levels for mites and aphids.
3.
Continue to develop mite and aphid life table data for the major hop varieties.
4.
Investigate natural enemies (parasitoids and predators) of mites and aphids on hops as
supplements to chemical control programs.
PROGRESS:
Foliar Sprays Yard III Yard III is planted with the cluster variety 'L,' on a 7x7 ft spacing, in plots 11
hills long, replicated three times were established in a completely randomized design. Treatment
combinations and rates are listed in Table 1. Spray applications were made using a hand gun operated
from a Rears air-blast sprayer at 140 psi (9.3 x 105 paseals) on the following dates:
Spray Volume
l/ha
Date
Time of Day
Temp (°F)
June 29
6:30-10:15 am
60-75
W 0-5 mph
1400
July 26
6:30-9:20 am
65-75
S < 5 mph
2100
Wind
gal/ha
150
225
Samples to determine the efficacy for mites, mite eggs, and aphids were taken July 5, 7, 12, 15, 20,
25, 28, and August 2, 8, 11, 16, and 19. Samples consisted often leaves picked from each plot, put
in labeled plastic bags and transported in styrofoam boxes to the laboratory where they were counted.
Leaves were processed through a mite brushing machine in the laboratory which deposited mites, eggs,
and aphids on a circular glass plate covered with a water-soluble sticky surface. The glass plates were
placed on a mechanical substage where a subsample representing one-tenth of the plate area was
counted using a binocular microscope (10X). Counts in Tables 1 and 2 represent numbers of individuals
per leaf. Although mite and aphid numbers were low, spider mites were the significant pest in 1994.
Results of the trials for mite control are presented in Table 1. Agri-Mek® at 0.02 lb Al/A, the principal
acaricide in this trial, compared with Omite® at 1.8 lbs Al/A and the untreated check. Again, working
with low numbers, and based on the season mean, Omite and Brigade had statistically significantly
more mites than any other treatment in the trial, including the untreated check. Agri-Mek + Brigade
was the same as the untreated check, but all other treatments were better than the untreated check.
Agri-Mek + CGA215944 + Silwet, Agri-Mek + CGA215944, Agri-Mek + Brigade + Dyne-amic, AgriMek + Pirimor, and Agri-Mek + Brigade + Silgard were the best treatments. No statistical differences
in these treatments for mite control existed. There were essentially no aphids in these plots throughout
the season as shown in Table 2. Some plants in this yard were used for other studies and were allowed
to stay past a normal harvest date. Aphid numbers increased in untreated plots and border rows to a
high level beginning in early September. Why they were not present during the growing season is not
known. Aphid migration into the yard in June appeared to be normal. Based on the season mean/leaf,
CONE
Page 1
there were more aphids in the untreated check plot than any of the treated plots and there were no
differences among the aphicides tested. Table 3 presents a comparison of mite and aphid numbers with
yields.
Foliar Sprays Yard II Yard II, planted with blocks of four hop varieties (L1, 'Galena', 'Olympic' and
'Nugget'), using five-hill plots (in the L1, 'Galena' and 'Nugget' blocks) replicated three times.
Treatments and combinations are listed in Table 4. Spray applications were made using a handgun
operated from a Rears air blast sprayer at 140 psi (9.3 x IP5 pascals) on the following dates:
Spray Volume
gal/ha
Date
Time of Day
Temp (°F)
June 30
6:40-11:30 am
55-70
S <5 mph
1400
150
July 27
8:50-10:20 am
70-80
W <5 mph
2100
225
July 28
6:30-9:45 am
60-75
W <5 mph
2100
225
l/ha
Wind
Sampling was done in the same manner as described for Yard III. Yield estimates were made by
harvesting the five best strings of hops in each plot and estimating bales/A based on the fresh weight
of harvested cones. Numbers in Table 4 are mites/leaf/date. There were no treatment differences, but
the untreated check was significantly different (P = 0.05) through late July and early August.
Foliar Sprays Yard III Azatin® and M-pede® The west half of Yard III was planted with 'Chinook' hops
in I993, but because of a weak stand, only part of the yard was used for this trial. Plots were 11 hills
long, separated by a single border row and were not replicated. Treatments were applied with a
handgun operated from a Rears air blast sprayer at 140 psi (9.3 x 105 pascals) and samples were taken
in the manner previously described. Sample dates were July 5, 7, 12, 15, 20, 25, 28, August 2, 8, 11,
16 and 19. Application dates are as follows:
Spray Volume
Date
Time of Day
June 28
9:50-10:50 am
July 27
7:15-8:30 am
Temp <°F)
Wind
l/ha
80
calm
1400
65-70
W 3 mph
2100
gal/ha
150
225
Mite and aphid numbers were very low throughout the season (see untreated, Table 6). Some of the
season mean numbers were statistically significant (P = 0.05), although there seemed to be no
relationship with the treatments (Table 6).
Drip Yard Systemics Plots were designed to test three rates of Admire® and Disyston ®and two rates
of dimethoate in each of four hop variety blocks and they were compared with an untreated check.
Application of these compounds was made June 23 using a four-head injection pump. Treatments and
rates are listed in Table 7. Leaf samples and yield data were taken in the same manner as described
previously in Foliar Sprays Yard III. Data for mites (Table 7) is included because field inspection during
August indicated a large difference in leaf color and appearance with the 2 lb. rate of Disyston. There
does not appear to be a corresponding reduction of mite numbers on increased yield to go along with
the field observation (Table 7 or 9). One point worthy of note is that a foliar application of Agri-Mek
(0.01 lb AI/A) + Kinetic (10 fl oz/100 gal) on August 2 was successful in reducing a large mite
population. Mites were severely injuring leaves at that time and application reduced mite numbers to
a low level and that persisted until harvest. Aphids found in these plots is presented in Table 8. The
season began normally with aphid numbers increasing during late June (see untreated, Table 8), but
during the remainder of the season, aphid numbers were low with no apparent explanation. This is the
third time in 33 years of project experience this has occurred. Table 9 shows the season mean number
of aphids and mites together with a yield estimate from each treatment for all varieties combined. The
only significant yield differences were that Admire 0.05 and 0.125 were better than Disyston 1.5. None
CONE
Page 2
of the treatments were significantly better (P = 0.05) than the untreated check. Yields for the varieties
(treatments combined) were 'Chinook' 8.436, 'Willamette' 6.098, 'Mt. Hood' 5.278, and 'Liberty'
4.558 bales/A.
Aerial application Roza Yard (Parker) The Roza hop yard consists of five variety blocks, 'Tettnanger',
'Banner', 'Nugget', 'Galena' and 'Willamette', each nine rows wide and 35 hills long. The entire yard
is surrounded by two border hills. The yard was sprayed by airplane using 10 gal water/A. The main
objective was to determine the effectiveness of Brigade and Admire for aphid control. The treatments
and the hop varieties treated are listed in Table 10. Aerial application was made about 6:00 a.m. on
July 2 under calm wind conditions with temperature at 66°F. Aphid numbers ranged from 7 to 46/leaf
prior to application. Subsequent counts on July 6 and 12 showed an increase in aphid numbers,
reaching a high of 283/leaf in the 'Banner' block. Diazinon was sprayed at 1.0 lb Al/A with an air blast
sprayer on July 13. Aphid numbers dropped to near zero in the leaf samples following that spray (Table
10). The weakness in this design was the lack of an untreated check, but the decline from several
hundred aphids/leaf on July 12 to near zero on July 15 with a foliar spray on July 13 seems to be more
than chance. Mite numbers began increasing during August (Table 10). A foliar spray using Agri-Mek
at 0.01 lb Al/A, Admire 0.1, and Kinetic 10 fI oz/100 was applied August 20, but no counts were made
after that. In summary, it appeared that aerial application of Brigade or Admire for aphid control on hops
was not satisfactory. Leaf samples were taken 5 to 6 ft from the ground and the assumption is lack
of spray coverage at that elevation. Several aspects of the design of this experiment that could be
improved for future work: 1) using this hop yard, fly one pass (one treatment) north-south on the east
edge and one pass (a second treatment) on the west edge, leaving the center of the yard untreated.
Such a pattern covers all five varieties with the same treatment; 2) sample the hop vines at several
elevations to determine if better coverage exists at elevations other than can be reached from the
ground.
Omite plus Gramoxone This trial evaluated the possibility that Gramoxone, used as an early-season
"burn-back" for crown growth, might have an effect on seasonal mite numbers by killing early-season
colonizing female mites. Two trials were conducted: one was on row 40 of the Roza yard ('Galena');
and the other was conducted in a grower hop yard ('Nugget'). The Roza yard application was made on
May 16 using 1.5 lbs Al/A of Omite 6E plus 0.75 lb Al/A of Gramoxone Extra in 106 gal water/A.
Temperature was 56°F and wind south at 5 mph. Foliage was sparse during late May and June.
Samples of 10 leaves taken at 5 to 6 ft above the ground were taken beginning July 1. The grower
yard application was made using an air blast sprayer. A portion of the center of the yard was left
untreated. Samples were taken from north (N) and south (S) treated areas as well as the untreated
center (C) area. Other sprays in the Roza yard were an aerial application of Agri-Mek plus Admire on
July 2, and an air blast sprayer application of Diazinon on July 13. The grower yard was sprayed
following a normal spray schedule that had no bearing on the Omite Gramoxone trial. Based on these
limited trials, there appears to be little difference between the treated and the untreated areas with
regard to mite population development. It is of interest to note the relatively large number of predator
mites that occurred in the Roza yard at a time when two-spotted spider mite number were increasing,
and appears that predator mites prevented further increase in spider mite numbers.
Black Vine Weevil The black vine weevil was a significant problem in several local hop yards in 1994.
Field counts of adult weevils following normal grower spray applications indicated no weevil mortality
due to aphid sprays. Microplots consisting of four hills replicated three times were established in a local
hop yard. Treatments and rates are listed in Table 12. Applications were made on June 8 using handsprayers and 51 gal water/A. Counts of living or dead weevils were made on June 13 by inspecting
each hill for two minutes (Table 12). Based on these preliminary counts, Furadan appeared most
effective, followed by the two pyrethroids Ambush and Cymbush. Admire showed no effect based on
these counts (which agrees with observations made following aphid spray applications using Admire).
Follow-up counts of larvae or pupae in late March or April 1995 will be made to help determine the
effectiveness of these treatments.
CONE
Page 3
Spray Table Evaluations for Aphid and Armyworm Control Two tests were conducted for control of
Bertha armyworm, Mamestra configurata, on hops. Field-collected larvae were tested in 15 x 15 cm
polyethylene petri dishes using rates of Brigade® in Test 1 and rates of Brigade and Dibrom® in Test 2.
Results of Test 1 indicated 100% mortality with 0.1 lb Al/A in one hour and with 0.0125 lb Al/A in
three hours. The lowest rate tested was 0.0015 lb Al/A which produced 100% mortality in three hours.
In test 2, Brigade at 0.0125 lb Al/A produced 100% mortality in two hours. Dibrom tested at four rates
produced 100% mortality with 1.0 and 0.5 lbs Al/A one hour. Lower rates (0.25 and 0.125 lb Al/A)
were effective after four hours. Two tests were conducted for control of the hop aphid, Phorodon
humuli, on hops. Hop leaves infested on the lower surface with aphids were collected from Cluster (L1)
hops at the WSU-Prosser. Leaf squares measuring 2 to 3 cm on a side and containing 20 to 100 aphids
were placed on cotton padding in a 15 x 15 cm square polyethylene petri dish. Various concentrations
of Brigade, Pirimor, Admire and Diazinon were applied using a spray table, and an untreated check was
sprayed with water. Pirimor at 0.2, 0.1 and 0.05 lb Al/A produced 99% mortality in two hours; 0.025
produced 60% mortality in two hours and 95% mortality in 18 hours. Brigade at 0.1, 0.05 and 0.025
lb Al/A produced 10 to 20% mortality in two hours and 96-100% in 18 hours. The 0.0125 lb Al/A rate
was almost as effective (9% at two hours and 98% in 18 hours). Admire at 0.02, 0.01 and 0.005 lbs
Al/A gave 35 to 70% mortality at 2 hours and 90 to 95% mortality at 18 hours. The low rate 0.0025
lbs Al/A was nearly as effective (20% at two hours and 98% at 18 hours). Diazinon was tested at 1.0,
0.5, 0.25 and 0.125 lbs Al/A gave 44 to 67% mortality at two hours and 94 to 99% mortality at 18
hours. Based on these finding, Pirimor (unregistered) is a superior aphicide, Admire and Brigade (Section
18's) are essentially as good as Pirimor, and Diazinon used at registered rates was satisfactory for hop
aphid control.
Reducing the Number of Hop Aphids on Hops by Spraying Plums Our experiment to reduce the number
of hop aphids on hops by spraying the aphid's overwintering hosts, plum trees, was expanded in 1994.
This year we sprayed the ornamental plum trees in the whole valley around Harrah, between Wapato
and White Swan, and used the Moxee area as an unsprayed control. A total of 235 plum trees were
located in the Harrah area. Landowners were contacted, permission to spray was obtained and 224
trees were sprayed with one application of Talstar [a formulation of bifenthrin (Brigade)] using a rate
of 3.2 oz/10 gal water applied from April 13 to 22. To see how well the spray worked, hop aphids on
10 shoots/trees from 36 trees on a transect of the Moxee area were counted on May 18 and 20, and
49 trees randomly selected in the Harrah area were sampled on May 20 and 23. Trees in the Moxee
area averaged 21.3 aphids/shoot, while the Harrah plums averaged 0.78 aphids/shoot. In a second
sampling, 31 plum trees were sampled on July 7 in the Moxee area and 36 trees on July 7 and 8 in the
Harrah area. In this sampling, we counted an average of 0.17 aphids/shoot in the Moxee area and no
aphids were found on the Harrah trees. Harrah area plums had much fewer aphids than Moxee trees,
indicating that one application of Talstar controlled the hop aphids very well. Hop yards were sampled
to see if the number of hop aphids on hops was different between the sprayed and unsprayed areas.
Sampling started during the week of June 13 and continued for eight weeks, concluding the week of
August 1. Fifty leaves were sampled per hop yard and 10 yards were sampled in each area per week.
The number of aphids on hops in the sprayed area was not statistically significantly different from the
number in the unsprayed area over the whole sampling season. The Harrah hops had an average of
2.80 aphids per leaf and the Moxee area had 2.56 per leaf (f = 1.335, P = 0.182, 7,998 df). Taken
one week at a time, the Harrah area had significantly more aphids than the Moxee area in three weeks,
the Moxee area had significantly more aphids in two weeks, and there>was no difference in three
weeks. Despite good control of the aphids on the plums and the large size of the sprayed area (about
130 square miles), the aphids were still able to infest hops in relatively high numbers, probably by flying
into the area from the surrounding unsprayed areas such as Yakima, Wapato, Toppenish, and White
Swan. Based on our knowledge of the hop aphid, the aphid depends on plums to complete its life cycle.
Therefore, reducing the number of overwintering aphids by spraying or removing plum trees should
reduce the number of aphids infesting hops. However, to be successful, the control measures would
have to be done over a very large area, probably the whole Yakima Valley.
CONE
Page 4
PROPOSED RESEARCH FOR 1995:
OBJECTIVES:
1.
Continue to screen and evaluate new compounds or combinations as they become available.
Provide samples for chemical residue analyses and pursue registration for the most promising
compounds. COST: All of the salary for the Technical Farm Laborer (6.3 mos.), timeslip wages
travel, half of goods and services and most of the fringe benefits are associated with this
objective.
2.
Develop a procedure for measuring pesticide resistance levels for mites and aphids. COST: Onequarter of the Res. Tech I time plus half of goods and services.
3.
Continue to develop mite and aphid life table data for the major hop varieties. COST: Onequarter of Res. Tech I time.
4.
Investigate natural enemies (parasitoids and predators) of mites and aphids on hops as
supplements to chemical control programs. COST: One-half of Res. Tech I time.
PROCEDURE:
Objective 1. We maintain three hop yards: 1) a 2-acre yard (half 'LV and half 'Chinook'); 2) a 1.7-A
yard with four varieties planted in blocks CLT, 'Galena', 'Olympic', and 'Nugget'); and 3) a 2.58-acre
subsurface drip-irrigated yard with blocks of four varieties ('Liberty', 'Mt. Hood', 'Willamette', and
'Chinook'). These plantings provide the area for establishing replicated small plots (7-11 hills each) in
a completely randomized design. These plots are used for testing new compounds for efficacy and to
provide hop cones for residue analyses. Specifically in 1995 we will continue to pursue and support
registration of Agri-Mek and Admire. Other compounds will be Pirimor (aphid control), CGA215944
(aphids), and fluvalinate (aphids). We will continue to pursue the use of biphenthrin (Brigade) for black
vine weevil control and control of fall armyworms on hops. Systemic insecticides will continue to be
tested using the subsurface drip irrigation system. In addition, the use of surfactants will be evaluated
for enhancing the activity of Agri-Mek.
Objective 2. We have been building an experience base with the spray table in the Faulkner Hop
Research Facility. This includes calibration of the system and conducting trials using pests (aphids,
mites, worms) or beneficial insects (three species of Coccinellid beetles). We anticipate trials with
predatory mites and green lacewings. This is a low level ongoing activity that stands ready should
resistance develop to currently registered compounds. We are also determining if beneficials have any
selective survival with registered or experimental compounds.
Objective 3. Again, this is a low-level ongoing objective that primarily uses data from the untreated
control plots in each of the variety blocks. If pursued at a higher level, we would use field-grown leaves
in small cages to determine the intrinsic rate of increase (rm) for aphids and mites on different varieties
of hops. This would best suit a grad student and will not be conducted in 1995 unless new resources
are found.
Objective 4. The main thrust of this objective for this proposal is to understand the overwintering
behavior of twospotted spider mites and the mite predator Typhlodromus occidentalis. The identity of
hills sprayed in the summer is maintained. Hop litter and soil is taken from those crowns, processed
through Berlese funnels, and the mites are inventoried. Samples are taken at weekly intervals from
October to March as conditions permit. Other portions of this objective being pursued include: 1) Bobbi
Callentine, aphid-predator interaction on hops (funded by Anheuser-Busch); 2) a joint project with Dr.
Keith Pike to study hop aphid parasitoids (funded by chemical company grants); and 3) Ludger
Wennemann, entomopathogenic nematodes to control June beetle and back vine weevil (funded by
chemical company grants).
CONE
Page 5
TIME FRAME FOR SPECIFIC OBJECTIVES:
Many of the functions carried out by the Res. Tech I and the Tech. Farm Laborer, overlap. In other
words, cultures maintained in the greenhouse can be used for several objectives. The maintenance of
the hop yards with several different varieties are used by several researchers and graduate students
which makes it difficult to prorate costs and establish time lines.
Objective 1: This is an ongoing project but specific objectives should be achieved. Brigade may be
registered in 1995 and Admire in 1996. Registration of Agri-Mek (1995? will depend on the outcome
of work done by Merck in 1994. Pirimor will move to a higher level of testing in 1995 and will probably
be an IR4 project in 1995. Registration will be several years (two to five) beyond that. Data for
surfactants in 1994 provide the second year of detailed evaluation. A minimum of three years are
necessary before conclusions can be drawn. Anticipate conclusive results following the 1995 or 1996
season. Systemics through the drip irrigation system will be an ongoing project. Keith Dorschner (IR4)
is interested in Disyston which could be cleared for this use in 1996 pending results from 1993-94
residue samples. Admire may gain registration for this use in 1996.
Objective 2. Procedures are in place to measure resistance levels of pests from area hop yards. We will
continue to use the spray table for efficacy against pests or selective survival of beneficials as
conditions permit. Minimal cost.
Objective 3. This objective is on hold until funding can be obtained to assign a graduate student.
Presently it is low level, ongoing with a minimum budget. Time frame when attempted will be a
minimum of three years.
Objective 4. We have three years of data (winter) and anticipate two more for completion in 1997.
CONE
Page 6
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0.125
1 qt
5 oz
0.02
0.1
Agri-Mek +
Brigade +
LI 700+
0.02
0.1
16 oz
Agri-Mek +
Brigade +
Dyne-Amic
Silwet
0.02
0.1
Agri-Mek +
Brigade
HHIIIHHHi IIIIIM
^^••••1
0.3a
0.3b
0
0.7b
0
0
0
0
0
0
HHHHHHHH
2.0a
Oc
0.3bc
0.3bc
Oc
1.b
Oc
Oc
Oc
Oc
0.7a
0
0
0
0
0
0
0
0
0
3.3a
2.3ab
Oc
Oc
2.7a
1.0b
Oc
0.3c
0.1c
0.3c
0.7bc
Oc
0.1c
0.1c
Oc
Oc
Oc
Oc
mean/leaf
Oc
Oc
llllll
Number of hop aphids/leaf in plots of hops ('L1') sprayed with insecticides and acaricides, WSU-Prosser, 1994, Yard III.
l$^lilll!l! lllllll liUlli
Table 2.
Table 3.
A comparison between the number of twospotted spider mites or hop aphids in plots
treated with insecticides or acaricides with the yield of hops, WSU-Prosser, 1994.
Season mean number fleaf
Treatment
Rate
(tbs Al/A)
Agri-Mek +
Brigade
0.02
Agri-Mek +
Brigade +
Dyne-Amic
0.02
Agri-Mek +
Brigade+
0.02
Agri-Mek +
Brigade +
Silgard
0.02
0.8de
Oc
10.390a
2.1cd
0.1c
9.028a
1.5cde
0.1c
11.603a
0.6de
0.3c
10.508a
0.2e
0.1c
10.005a
1.1de
0.3c
9.443a
7.0a
Oc
9.028a
2.1cd
1.0b
9.502a
4.5b
2.7a
9.679a
0.1
1.5 pts
0.02
0.178
0.02
0.178
Silwet
5 oz
Agri-Mek +
0.02
Pirimor
0.25
Omite +
1.8
Brigade
0.1
Omite +
1.8
Pirimor
0.125
Untreated
8.465a
0.1
1 qt
CGA215944 +
Oc
16oz
5 oz
Agri-Mek +
3.2bc1
bales/A
0.1
Silwet
CGA215944
Aphids
0.1
LI 700 +
Agri-Mek +
Hop Yield
Mites
. . . .
Numbers not followed by the same letter are significantly different (P&0.05) DMRT.
CONE
Page 9
o
CD
era
13
o
8<S£
Dyne-amic
Dyne-amic
Dyne-amic
Kinetic
Kinetic
Kinetic
Penetrator-Plus
Penetrator-Plus
Penetrator-Plus
+
+
+
+
+
+
+
+
+
Dyne-amic
Kinetic
Kinetic
Kinetic
Penetrator-Plus
Penetrator-Plus
Penetrator-Plus
+
+
+
+
+
+
+
0
0
0.3
1.7
4.3
0
16.0
0.3
8.7
0.3
9.3
1.0
8.0
2.0
17.0
3.7
4.0
1.3
0
1.0
1.7
0.3
0.7
0.3
0.3
0
0
0
0
i t o?
0.3
1.1def
4.7
2.7
1.7
1.3
1.3
0.7
0
0
0
0
0
8 oz
0
1.4bcdef
3.3
5.7
2.7
2.7
0.7
0.7
0
0
0
0
0
0
2.4bcdef
5.5
10.
4.0
5.5
1.5
3.0
0
0
0
0
0
9 oz
0
G.4ef
0
2.0
0.5
0
0.5
1.0
0.5
0
0
0
0
6oz
6.3a
0.8Zftf
<Uf
1.1 cdef
2.3
4.3
1.0
1.3
0.7
1.3
0.3
1.0
0
0.3
0
»3 oz
4 oz
0.4ef
0.3
1.3
1.3
0
0
0
0.3
0.3
0
0
Numbers not followed by the same letter are significantly different (P&0.05) DMRT
Untreated
1.1def
6.0
3.0
0.3
0.3
0.7
1.3
0
0
0
0
0.3
0
32 oz
16oz
Dyne-amic
+
1.9bcdef
4.0
13.7
0.3
0.3
0.3
1.7
0.7
0
0
0
1.5bcdef
7.0
4.0
2.7
1.0
0.7
0.7
0.3
0
0
0
0
16oz
0
2.5bcde
4.3
9.7
4.3
3.7
1.7
2.0
0.7
1.0
0
0
0
12oz
8 oz
3.0bcd
5.0
10.7
7.0
6.0
2.0
2.0
0
0
0.3
0
0
8 oz
Dyne-amic
3.5b
5.7
13.0
6.3
10.3
2.3
0.3
0.3
0
0
0
0
9 oz
+
2.0bcdef
2.7
5.3
3.3
4.3
2.7
2.0
0
1.3
0.3
0
0
6 oz
0.2 oz
Penetrator-Plus
3.2bc
7.0
10.3
3.7
5.0
2.0
2.7
3.7
1.3
0
0
0
3 oz
Agri-Mek
+
0.$ef
1.5
2.0
0.5
1.0
1.0
0
0
0
1.0
1.3cdef
1.0
6.0
1.0
2.7
0.3
3.3
0
0.3
0
0
0
Q,8ef
1.7
0.7
1.7
0.7
0.3
0
3.3
iYiYiTiiiHUiUiiiii
iiiiiiill
llllillllllllIlilllllillMllWIM
0.3
iililllillll
0
ill
:lliliiffi||i
0
0
0
1111
Date
&2Q*
16oz
CM m
Agri-Mek
0
iiiiiiiiiiiiiii
iiiiii^iiiiiii
miY|Yi'i'i'mi I i.i.i.i.n. 1.1.1 n .'.'.Hi.'.' .'•' J.1.1.1.'.'.'.'•' •'•' J.1.1.1.1.1.1.1.1.1.1.1.1.1
nnViiij^
Number of twospotted spider mites/leaf in plots of hops treated with two rates of Agri-Mek®, Admire® at 0.1 lb Al/A and a
series of surfactants, WSU-Prosser, 1994, Yard II.
Treatment
Table 4.
Table 5.
Relationship between season mean number of mites or aphids/leaf and yield of hops in
plots treated with an acaricide + and aphicide + a surfactant, WSU-Prosser, 1994,
Yard II.
Season mean number/leaf
-
Rate
Treatment
[lbs Al/A)
AgriMek
0.1 oz
Mites
Aphids
Hop Yield
bales/A
+
Dyne-amic
8 oz
0.79ef
0.09c
8.096a
+
Dyne-amic
16oz
1.33cdef
0.12c
7.413a
+
Dyne-amic
32 oz
0.57ef
0.07c
8.17a
+
Kinetic
3 oz
3.24bc
0.15c
+
Kinetic
6 oz
2.0bcdef
0.09c
8.532a
+
Kinetic
9 oz
3.48b
Oc
8.051a
+
Penetrator-Plus
8 oz
3.0bcD
0.09c
7.148a
+
Penetrator-Plus
12oz
2.48bcde
0.82b
7.755a
+
Penetrator-Plus
16oz
1.48bcdef
0.27c
7.045a
AgriMek
0.2 oz
+
Dyne-amic
8 oz
1.91bcdef
0.06c
7.282a
+
Dyne-amic
16 02
1.06def
Oc
9.094a
+
Dyne-amic
32 oz
0.36ef
0.06c
7.104a
+
Kinetic
3 oz
1.15cdef
0.15c
8.14a
+
Kinetic
6 oz
0.36ef
0.04c
8.969a
+
Kinetic
9 oa
2.36bcdef
Oc
9.812a
+
Penetrator-Plus
4 oz
1.42bcdef
0.12c
7.933a
+
Penetrator-Plus
8 oz
1.12def
Oc
8.673a
+
Penetrator-Plus
12 (52
0.30f
O.OjBc
10.434a
+
Penetrator-Plus
16 02
0.82ef
0.18c
9.42.4a
6.3a
3.2a
6.956a
Untreated
Numbers not followed by the same letter are significantly different (P^0.05) DMRT
CONE
Page 11
Table 6.
Effectiveness of Azatin® and M-Pede® alone or in combination for control of twospotted
spider mite and hop aphid on 'Chinook' hops, WSU-Prosser, 1994.
Season mean number/leaf
Yield
Mite
200 lb
Treatment
Rate
Mites
eggs
Aphids
bales
M-Pede
1%
4.5bc
3.5c
1.3bc
13.320
M-Pede
2%
9.5bc
12.8a
1.1c
13.142
Azatin
7.5g
10.8bc
7.1bc
2.8ab
11.455
Azatin
15g
8.8bc
5.0bc
1.4bc
10.212
M-Pede+
1%
6.2bc
8.2bc
3.2a
11.810
Azatin
7.5%
M-Pede+
1%
4.1C
4.5bc
2.7bc
9.857
Azatin
15g
11.3a
10.6bc
2.3bc
13.054
11.2ab
11.8ab
2.0bc
7.637
4.5bc
4.2c
1.8bc
11.011
M-Pede+
2%
Azatin
7.5g
M-Pede+
2%
Azatin
15g
Untreated
. . . .
Numbers not followed by the same letter are significantly different (P£0.05) DMRT
Number of mites/leaf in plots treated with systemics through a drip irrigation system
June 23 and a foliar spray with Agri-Mek (0.1 lb Al/A) plus Kinetic (10 fl oz/100 gal)
on August 2, WSU-Prosser, 1994.
Table 7.
|||ii|l;
lljcswiiwiftrill
Al/A)
|g|i^i8i^^;|gi|i;
lliHII
IIBiiiilii ||pi|BjSs||:
lllili 111 lllllll llllll 1111 lllllll ilii III! lllllllll 11111111
Admire
0.05
0.8
0.8
10.5
12.5
19.8
41.5
73.8
3.0
3.5
.8
0.8
0.3
Admire
0.125
1.8
1.5
5.0
23.5
34.8
39.0
84.0
3.2
4.2
3.5
3.0
1.0
Admire
0.25
0.8
0.5
5.5
9.0
23.5
55.8
85.0
3.5
2.2
0.8
0.8
0.3
Dimethoate
1.0
1.8
1.0
2.3
12.5
14.8
26.8
69.2
3,.8
6.2
1.8
2.5
3.0
Dimethoate
2.0
0
0.8
2.0
4.5
9.0
25.5
63.7
2.5
1.2
1.8
2.2
0
Disyston
1.0
1.8
1.0
3.0
8.5
14.2
23.5
64.5
5.0
2.0
0.5
0.5
0.5
Disyston
1.5
1.3
2.8
5.5
8.8
16.0
61.2
114.8
4.2
1.5
4.2
2.0
0.8
Disyston
2.0
0.8
2.5
4.0
11.0
17.8
35.8
90.5
2.8
5.8
1.2
3.8
1.2
—
2.5
1.3
5.5
9.5
16.0
24.8
71.75
1.8
2.5
1.2
1.2
0.8
Untreated
Foliar spray for mite control August 2.
CONE
Page 12
o
ft
OQ
13
.ff
o
•z
1
1.5
2
Disyston
Disyston
Disyston
— -
0.2
4.8
14.2
2
Dimethoate
Untreated
0.2
4.0
7.0
1
Dimethoate
*"
1.0
3.2
6.5
0.25
Admire
1.3
1.8
32.3
5.5
0.5
4.0
5.0
6.0
10.5
1.3
1.5
1.3
15.2
0.125
Admire
10.
1.0
7.2
6.0
0.05
Admire
12.8
30
27
22
Rate
(lbs Al/A)
•June
0
0
0.2
0.3
0
0
0
0.3
0
1.3
0
0
0
0.5
0
0.2
0
0
0
0.5
0
0.2
0
0
0
0
0
0
0
0
0
0
0.2
10.3
0
0
0.5
0
0
1.5
0
0
0
1.7
0.2
0.2
0
1.2
0
0
1.5
0
0
0.3
0
4.2
0
0.5
3.5
0
0.2
0.3
0.8
0
0
0
0
0
0
0
0.2
0
0
0
0.5
0
0
0
0
0
0
0
0
0
0
0
1.3
0
0
0
0
0
0
0
0
0
0
0
0
23
18
15
10
s
1
26
21
19
13
August
7
July
Date
Number of aphids/leaf in hop plots treated with systemic aphicides in a subsurface drip irrigation system, WSU-Prosser, 1994.
Treatment
Table 8.
Table 9.
Comparison of season mean numbers of mites or aphids/leaf with yield of hops from
plots treated with systemics through a drip irrigation system, WSU-Prosser, 1994.
Season mean number/leaf
Yield
200 lb
Rate
Treatment
(lbs Al/A)
Mites
Aphids
bales/A
Admire
0.05
13.9a1
1.0b
7.104a
Admire
0.125
17.a
1.3b
6.860ab
Admire
0.25
15.6a
0.8b
5.706bc
Dimethoate
1.0
12.1a
0.9b
6.083bc
Dimethoate
2.0
9.4a
1.4b
5.639bc
Disyston
1.0
10.4a
1.8ab
6.017bc
Disyston
1.5
18.6a
1.5b
4.995c
Disyston
2.0
14.7a
0.8b
6.282bc
11.6a
4.0a
6.149bc
Untreated
. . . .
Numbers not followed by the same letter are significantly different (P>0.05) DMRT.
CONE
Page 14
n
13
o
0
46.3
aphids
20.3
aphids
mites
0
mites
72.3
0.3
6.7
0.7
*
**
1.3
37.0
aphids
7.0
.aphids
mites
0.3
mites
Aerial application made July 2.
Foliar diazinon spray July.
'Willamette'
'Galena'
61.7
0.3
52.0
0.7
Admire 0.1 + Agri-Mek 0.02 + Kinetic 10 oz/100
'Banner'
'Tettnanger'
iii^iiiiiiii
:'':':":':':':':':':':':':':':':':':':'ifititititillftitiffin
Prosser, 1994.
18.3
0.3
25.3
2.3
283.7
0.3
26.3
1.0
0
0
0
0.7
0
1.0
1.7
1.3
0.7
0.3
1.7
0
0.3
1.0
10.0
0
9.7
0
9.3
15.7
0.7
0.7
0.3
31.0
10.3
8.7
3.3
1.3
0
8.7
0.7
3.0
0
3.3
0.3
1.3
0
4.7
0.7
1.0
0.3
1.0
!11 !•!!!! 1!!!!!!!!!1!!!1!1!!!!!!!!!
0.3
1.3
0
0
0
1.3
Date
0
4.7
0.3
5.0
2.0
47.7
0
5.3
5.7
2.0
22.7
6.3
0.7
1.0
0.3
0
2.0
1.7
1.3
0.3
1.0
4.0
4.0
7.3
Numbers of mites and aphids found on four hop varieties treated with an aerial application of insecticides and miticides, WSU-
Treatment and
Table 10.
o
CD
w
o
0
0
0
0
3
0
8
90
2
0
1
7
5
15
20
25
28
August
8
3
1
27
13
0
10
2
0
11
16
18
mfte
2
2
3
tttjg*
2
2
15
36
6
9
8
10
0
2
15
26
8
9
9
10
3
2
0
mite
4
1
0
1
1
0
0
0
0
42
85
3
aphid
Untreated
0
0
0
0
11
11
0
1
0
5
1
0
1
3
0
0
22
3
0
0
ttUtA
0
0
0
0
pt£<f
0
0
0
49
0
0
0
0
0
0
1
3
0
0
0
0
33
0
0
1
0
aphid
23
2
0
*ggs
tnfte
Treated \H\
Predators are the western predatory mite, Typhlodromus occidentalis.
0
7
0-
2
3
0
2'
0
0
0
0
0
0
0
pi*d
8
12
1
10
4
12
2
59
15
0
8
aphid
mite
aggs
0
0
rtMtS
Treated
Bora Yard ('Galena')
0
0
28
36
31
0
8
3
10
10
11
0
0
0
0
0
0
0
0
0
10
0
0
0
0
1
1
0
0
0
0
0
0
0
0
0
5
6
0
0
pred
0
0
0
0
0
0
0
0
0
1
10
0
aphid
1
10
0
fegtj*
miia
p«sd
ntfte
Untreated <C)
Grower Yard (*Nugget')
mite
0
0
0
0
21
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
43
1
0
18
2
27
0
0
aphid
3
0
sggs
2
1
mitt
Treated <SJ
0
0
0
0
0
0
0
0
0
0
0
0
pwd
Numbers of mites, mite eggs, aphids and predators found in plots of hops treated with Omite® 6E and Gramoxone®, Yakima
Valley, WA, 1994.
6
1
July
Date
Table 11.
Table 12.
Numbers of living or dead black vine weevil adults in plots of hops treated with
insecticides, Yakima Valley, WA, June 13, 1994.
fAean number/Kill
Rate
Treatment
Admire
Bridgade
(lbs AI/AI
0.3
0.1
1
Furadan
Ambush
Cymbush
Untreated
Untreated
CONE
0.2
0.2
— -
—
Rep
Living
Dead
A
2.75
0
B
2.25
0
C
6.6
0
A
1.75
0
B
1.25
0.5
C
2.25
0
A
1.0
0.5
B
0.5
1.75
C
1.75
1.75
A
1.0
0
B
25.0
0.25
C
1.25
0.25
A
0.5
0
B
3.75
0.25
C
2.5
0
A
1.75
0
B
3.5
0
C
2.0,
0
Page 17
PROJECT NO.:
4379
TITLE:
Hop Diseases and Their Control
PERSONNEL:
Project Leader:
R. E. Klein, Assistant Plant Pathologist, WSU-Prosser
M. E. Nelson, Agric. Research Tech III, WSU-Prosser
S. D. Husfloen, Lab. Tech II, WSU-Prosser
T. J. Estep, Tech Farm Laborer, WSU-Prosser
PROJECT OBJECTIVE:
Identify, investigate, and ameliorate losses caused by pathogens of hop.
REVIEW OF 1993 WORK:
Monoclonal antibodies were used to detect and evaluate ilarviruses of hop. Although they are both
called Prunus necrotic ringspot, the monoclonal antibody tests confirmed preliminary data which
indicated that the ilarviruses from hop and Prunus spp. are very different. Earlier reports by Skotland
and Haunold that the hop ilarviruses did not appear to be seed-transmitted received preliminary
confirmation in crosses between a limited number of infected males and healthy females and between
infected males and females. In the first year of foliar micronutrient tests, solutions of zinc, boron, and
calcium did not increase alpha-acid concentrations in treated 'Galena' hop, regardless of virus infection
status. Virtually all toxicity observed with historical applications of heptachlor and chlordane is
associated with heptachlor and heptachlor epoxide and, at most, only minor damage can be attributed
to other components of the chemical formulation, including chlordene and the isomers of chlordane and
nonachlor.
OBJECTIVES FOR 1994:
Investigate serological variability, transmission characteristics and chemical control of ilarviruses.
Develop data to support fungicide registration and develop control programs for hop downy mildew.
Develop new detection methods for the detection of hop pathogens with special emphasis on
Verticillium and other systemic fungal pathogens. Screen advanced experimental cultivars for
susceptibility to various diseases including downy mildew and heptachlor. Investigate epidemiology of
hop carlaviruses. Determine the incidence of viruses in the hop-growing areas. Monitor and enhance
production of virus-free hop rootstock.
ACCOMPLISHMENTS FOR 1994:
Polyclonal antisera and monoclonal antibodies were used to further define hop ilarviruses. As expected,
two major groupings which corresponded to the necrotic ringspot (NRSV) and apple mosaic (ApMV)
strains were detected. However, there was considerable serological variability within each group and,
in some cases, particular serotypes of NRSV were associated with disease while other serotypes
appeared to be symptomless. Transmission of NRSV was associated with root and foliar contact
between healthy and infected plants. New antisera were prepared against various Verticillium isolates.
These antisera separate V. dahliae and V. albo-atrum in Western blot tests and also will differentiate
some V. albo-atrum isolates. Evaluation of experimental clones was continued and expanded.
Epidemiology of hop carlaviruses was investigated in continuing research. As in earlier years, hop latent
(HLV) and American hop latent (AHLV) viruses spread to healthy plants at a much greater rate than hop
mosaic virus (HMV). Spread of each virus was independent of other viruses, but infections were
clustered around previous infections. A virus survey was conducted throughout the tri-state hop
growing areas. HLV and AHLV were the most prevalent and ApMV the least common viruses,
regardless of growing area. HMV incidence varied most widely depending on the hop cultivar. NRSV
incidence differed among varieties and states but was much higher than originally anticipated. Tissue
KLEIN
Page 18
culture records were evaluated to determine how best to speed virus eradication and plantlet
regeneration. The time of year of meristem excision had no discernable influence on tissue culture
duration but a pedigree containing Brewer's Gold was associated with recalcitrance in tissue culture.
KEYWORDS:
diseases, downy mildew, fungicides, viruses, heptachlor
PUBLICATIONS:
None
PROGRESS IN 1994:
Downy Mildew -Variety trials. Experimental hop clones wereevaluated for downy mildew susceptibility
by counting the number of primary and secondary spikes present on May 18, 1994. Each clone is
evaluated as a single non-trellised plot, 20 ft. long with a 12-in. plant spacing. Inoculum originates from
nearby hop plants which have been specially selected for their ability to produce inoculum. Inoculum
is allowed to spread under natural environmental conditions except for sprinkler irrigation.
Number of
Number of
Spikes
Hop Cone
Spikes
21660
2
8254-167
5
21661
3
8695-003
0
21662
3
8553-065
0
21663
3
8657-042
1
21664
0
8694-002
0
21666
0
8696-003
Too small to evaluate
Kita-Midori
2
'L1' Check
31
Hop Cone
It was obvious after last fall's evaluation that 'L1' alone was not an adequate check to determine
potential susceptibility. Consequently, additional check varieties were added this spring along with
additional experimentalclones including the triploid 'Saazer' clones. The downy mildew evaluations now
include 26 varieties and clones.
Downy Mildew - Fungicides. The combination of the virus survey in May and June and the unusually
hot weather in July made further tests with DW-92 impossible in 1994. Expanded tests including
combinations with spray adjuvants are planned for 1995.
Ilarvirus Detection and Serological Characterization
Effects of ilarvirus infection in hop can be severe
and ilarviruses are widely considered the greatest virological problem of hop. Despite their economic
impact, little is known about their biology. Dr. Skotland collected many ilarvirus isolates as infected hop
plants during his tenure at WSU and even casual observation demonstrates a wide range of symptoms
and disease severity among the plants within this collection. These virus isolates can be separated into
two serological groups, NRSV and ApMV, but these serogroup designations have little or no correlation
with symptom severity. Consequently, we became interested in ilarvirus strain differentiation in order
to better assess disease problems. A range of serological reagents including polyclonal antisera and
monoclonal antibodies were used to test 91 ilarvirus isolates. Polyclonal antisera against NRSV-hop and
ApMV-hop clearly separated the isolates into the NRSV and ApMV serogroups (Figure 1) as previously
reported by others. As indicated in Figure 1, the isolates exhibit a wide range of serological activities
and the differences among isolates was repeatable. In the few cases tested, virus isolates which appear
to be symptomless in their hop host have low NRSV O.D./ApMV O.D. ratios, while the more severe
isolates have high ratios. Monoclonal antibodies did not separate the NRSV and ApMV serogroups, but
a subset of ApMV isolates failed to react with a particular monoclonal antibody (Figure 2). Although
this allows a clear and unambiguous isolate identification among members of the ApMV serogroup, this
KLEIN
Page 19
difference has not been associated with symptomatic differences. Serological differentiation of hop
ilarviruses remains difficult because variability between tests done at different times is high. Virus
isolates from the extreme ends of the serogroup distributions are easily differentiated, but it will be
difficult to separate isolates with minor serological differences. However, the ability to differentiate
isolates within serogroups will allow us to investigate viral cross-protection as a possible virus control
method.
Verticillium Serology Polyclonal antisera were produced in rabbits against antigens partially purified
from a hop isolate of V. albo-atrum and from a peppermint isolate of V. dahliae. Both isolates were
obtained from the American Type Culture Collection. Tests designed to distinguish between Verticillium
species and isolates within a species are currently being developed with these antisera. Verticillium
isolates from a wide variety of hosts are used to evaluate the activity of the antisera. Verticillium
species lateritium, nigrescens, nubilum, and tricorpus are differentiated by these antisera in western
blots. In spite of their close serological relationship, preliminary results suggest that albo-atrum and
dahliae may also be separated using these techniques. Procedures need to be refined to obtain the
consistent results needed for routine testing. More sensitive tests may be needed to differentiate
isolates within species.
Carlavirus Epidemiology
The goal of plant pathological research is to reduce or eliminate
economic losses due to disease. Disease, as inferred by the presence of parasites such as viruses and
viroids, invariably causes losses, regardless of symptoms or lack thereof. These losses, however, may
be small and difficult to demonstrate or detect in small plots. If the cost of pathogen control is lower
than the projected loss, control of even the most minor pathogen is needed. This, I feel, is the case
with the hop carlaviruses. Losses due to virus infection are small and cannot be reliably detected in the
small test plots used. The same was true of related viruses in potato and until plots were expanded to
include acres, many people felt there was no economic loss associated with carlavirus infection in
potato. Based on the research on potato viruses and consistent with work done on hops, hop yield
losses of 2 to 5% due to carlavirus infection seem likely. Epidemiological data is needed to determine
which, if any, economical control methods are possible. In 1986-1990, Skotland and Kenny conducted
an experiment to determine effects of virus infection on yield in three hop varieties. The experiment
could not be conducted as originally planned due to rapid carlavirus spread throughout the plots. Kenny
reported the yield data in his annual reports from those times while Skotland briefly reported virus
incidence in the 1989 and earlier research reports. A few years ago, the data collected by Skotland and
Kenny were re-examined to resolve a few discrepancies and to determine the rates of spread of the
three carlaviruses, HMV, HLV, and AHLV. Yearly virus incidence and rates of spread are shown in
Figure 3a for the carlaviruses and the ilarviruses. Data indicates HMV spreads slowly while both HLV
and AHLV spread quite rapidly. Unfortunately, data is strictly observational and lacks the rigor of a
designed experiment and it was not possible to discern patterns of spread, virus interactions, etc. Thus,
a thorough and planned experiment was needed to better understand carlavirus epidemiology. As
discussed in last year's report, a plot was established at the Roza Unit to examine carlavirus
epidemiology in 'Nugget' hops. An update on virus spread is presented in Figure 3b; the differences
among the viruses can be enhanced by accounting mathematically for repeated inoculations of
previously infected plants and expressing the results as number of infections (Figure 3c). Analysis of
the spatial distribution of the infected plants indicates that virus infections are independent (infection
by one virus is not positively or negatively associated with infection by other viruses). Infections
occurred randomly the first year but, in the second year, new infections were significantly associated
with previously infected plants (P<0.10 for HMV and HLV, P<0.01 for AHLV). This experiment will
continue for one or two more years and numbers may change slightly when a more sophisticated
analysis is conducted on the entire data set. Although conclusions are tentative because the experiment
is not yet complete, HMV seems to be an excellent candidate for control. Although the virus is aphidtransmitted and can spread between hop yards, the rate of spread within a hop yard is low. Thus, a
hop yard planted with HMV-free rootstock should remain substantially free of HMV for many years. And
because HMV freedom can be included (and has been since 1991) in the certified rootstock program
at no further expense, control of potential losses is economical. Although HLV and AHLV freedom have
been included similarly, it seems unlikely that hop yards will remain substantially free of these viruses
KLEIN
Page 20
for an extended period of time. Control of HLV and AHLV is likely to be difficult and may not be
justified economically.
Hop Virus Survey
A virus survey was conducted to determine virus incidence in major hop
varieties grown in each state. The number of hop yards sampled was approximately in proportion to
the hop and varietal acreage within each state, with a slightly greater number of yards sampled for
relatively minor varieties to insure statistical validity. Twenty samples, each consisting of the terminal
15 cm of a hop vine were collected at random from each sampled yard regardless of the size of the hop
yard. All sampling was done during May and June while temperatures were cool and virus detection
most reliable. Samples were tested for the two hop ilarviruses, NRSV and ApMV, as well as for HMV,
HLV, and AHLV carlaviruses. Survey results are shown in Table 1. ApMV was detected in only 1 % of
the samples and infection by this virus seems to be of little economic concern. Incidence of NRSV
varied by hop variety and, to a limited extent, by state. Some of the variability is likely due to the
certified rootstock program in WA. For example, NRSV incidence in 'Willamette' is high in OR but low
in WA. All 'Willamette' hops in WA trace back to virus-free material from the program while OR does
not have a similar program. On the other hand, some lapses within the program became apparent. All
'L1' and 'L8' Cluster hops are infected with NRSV and , in the case of those originating from the
rootstock program, with a single serological strain of NRSV. Five years ago, it was determined that the
'L1' and 'L8' mother plants maintained at WSU-Prosser were infected with NRSV. Apparently, these
plants had become infected many years earlier and the re-infection had gone undetected because these
strains are apparently symptomless and are present only in low concentrations. This stresses the need
for repeated testing of all materials using the most sensitive techniques available. Infection by HLV and
AHLV was very common. Indeed, most plants, regardless of variety, are infected with these viruses.
HMV, on the other hand, tended to be relatively uncommon. These results are quite different from those
reported in Great Britain, Germany, and the Czech Republic. In Europe, ApMV is more prevalent than
NRSV and HMV is more common than HLV. It is not clear whether these differences are due to different
virus strains, different environments, or different virus vectors. Results also indicate that there is much
room for improvement in ilarvirus control in each state if losses due to disease are to be reduced.
Tissue Culture and Plant Propagation About 1100 softwood cuttings of 18 different hop varieties and
experimental clones were propagated in 1994. Crowns from these plants will be harvested in 1996 and
made available through the WHC to certified rootstock propagators. During the past four years,
approximately 40 hop varieties and experimental clones have gone through the tissue culture/virus
eradication program at WSU-Prosser. The number of requests from researchers, brewers, and growers
for virus eradication has been tapering off and it appears that all industry requests for this service have
been met. We anticipate there will be increased demand when the varietal evaluations now underway
are completed. In our tissue culture/virus eradication process, cultured plant tissue goes through three
steps in the laboratory. Excised apical meristems are cultured in liquid medium to encourage shoot
elongation (Step 1), elongated shoots are cultured on solid medium to encourage rooting (Step 2), and,
finally, rooted shoots are grown in potting soil to establish and harden the plants for greenhouse culture
(Step 3). The dates at which each manipulation was performed are recorded for each culture. We have
analyzed these records to determine which, if any, culture parameters contribute to ease or difficulty
of culture. For several years, we thought that plant tissues excised in the spring grew into plantlets
more quickly than tissues excised at other times of the year. Data analysis did NOT support this.
Instead, time requirements for plantlet regeneration are independent of timte of excision as long as the
plants are growing vigorously and not becoming dormant.
For each virus-free plantlet obtained, several plantlets are usually regenerated and, for the 40+ clones
for which virus-free plantlets have been obtained, 30 clones had at least 10 plantlets regenerated.
Average number of days required for plantlet regeneration as well as number of days required for each
step of the tissue culture procedure was calculated for each of the 30 clones. Number of days required
for plantlet regeneration ranged from 64 to 140 and the means appeared to be bimodally distributed.
Clones were subsequently divided into two groups of 15 clones each based on total regeneration time.
Group A clones required 64 to 93 (average 80.3) days and group B clones 109 to 140 (average 124.5)
days for plantlet regeneration. The two groups did not differ in time required for shoot elongation but
KLEIN
Page 21
were significantly different (P=<0.05) in the amount of time required for rooting and plant
establishment. Summary statistics are shown in Table 2. Rooting and plant establishment are associated
variables and virtually the entire difference between the two groups is associated with their to rooting
medium. Dr. Kenny determined the pedigrees of the various clones and noted that 10 of 15 group B
clones, but only 2 of 15 group A clones had 'Brewer's Gold' in their respective pedigrees. Thus, it
appears that recalcitrance in tissue culture has a genetic basis. Preliminary tests suggest that high
concentrations of cytokinins may help overcome this recalcitrance, but this may also cause tissue dedifferentiation and callus formation.
The regeneration of plantlets from callus culture (or single cells) is a critical aspect of any future genetic
engineering of hop. Although researchers in Great Britain reported this several years ago, they have
failed to publish a protocol and their work has not been verified in other laboratories. Researchers in
the Czech Republic recently reported plantlet regeneration from callus cultures initiated from leaf blades,
petioles, and stem internode segments. Percentage of cultures regenerating plantlets varied with the
source of the callus culture but did not exceed 52% after 4 months. Interestingly, high cytokinin
concentrations are used to induce callus formation. We have begun experiments to verify this work.
It is still too early to judge success, but we have regenerated a single plant on callus induced under high
benzyladeninepurine concentrations. We have not yet used zeatin, the cytokinin with which the Czechs
had their greatest success. There is some evidence suggesting clonal variability in callus culture
formation, and may indicate that particular varieties and clones will be recalcitrant in this type of tissue
culture as well. Regenerated plantlets from these experiments will be used to assess somoclonal
variation in tissue culture.
1995 RESEARCH OBJECTIVES AND % ESTIMATED COST BREAKDOWN:
1.
Continue and expand the virus-free hop rootstock program. BENEFIT: A ready supply of
clonally-controlled, virus-free hop rootstock. (35%)
2.
Investigate the feasibility of viral cross-protection for the control of ilarviruses in hop. BENEFIT:
A long-term control method suitable for situations inappropriate for virus-free rootstock. (15%)
3.
Test potential fungicides for control of downy mildew. BENEFIT: Continued reliable control of
downy mildew. (5%)
4.
Expanded emphasis on hop crown health. This is an unavoidably broad objective and will
require fine tuning over the years. BENEFIT: Identification of factors which lead to hop decline.
(10%)
5.
Continue research on pathogen diagnosis, especially development of diagnostic reagents.
BENEFIT: Continued and expanded diagnostic services. (20%)
6.
Evaluate the response of new varieties and other experimental materials to various diseases.
BENEFIT: Selection of new varieties with acceptable horticultural characteristics. (15%)
PROCEDURES AND TIME FRAME:
Many of the above objectives are ongoing programs without specific objectives.
Components of Objective 2 are discussed as follows: Two ilarviruses, Prunus necrotic ringspot
(PNRSV) and apple mosaic (ApMV) viruses, commonly infect hop. Infection by these viruses can
significantly reduce hop yield and quality, depending on the variety, the environmental conditions, and
the virus strain. These potential yield losses have justified the long-standing ilarvirus-free hop rootstock
program, operated cooperatively by the WHC, WSDA, and WSU. This program, without doubt, has
reduced the incidence of PNRSV/ApMV and helped alleviate yield reductions throughout the Yakima
Valley and especially among growers who use virus-tested rootstock. However, a recent survey of hop
KLEIN
Page 22
yards in the Yakima Valley indicates that the incidence of PNRSV/ApMV still exceeds 50% and there
is obviously room for improvement in the control of these viruses. Justification: It has frequently been
observed that prior infection of a plant by one virus can prevent infection of a closely related virus or
virus strain. This phenomenon, termed viral cross-protection, has some similarities to vaccination in
animals, but operates on a different and poorly understood mechanism. Cross-protection has been
documented in sweet cherries infected with various strains of PNRSV and some growers purposefully
use trees infected with mild or nonsymptomatic strains of PNRSV in an effort to avoid later infection
by more severe PNRSV strains. We have several observations that infection by different strains of
PNRSV/ApMV cause different symptoms in hop and that these symptoms may range from severe to
mild to nonsymptomatic. There is also evidence that cross-protection occurs in ilarvirus-infected hop
plants. Although we have long separated ilarviruses in hop into PNRSV and ApMV, it has only recently
become possible to differentiate some isolates within these broad categories. We have observed
serologically different strains of PNRSV in 'Nugget' hops, one which causes symptoms and one which
is apparently nonsymptomatic. Similar observations were made in 'Galena' hops. 'Cluster' hops
originating from the rootstock program have apparently been infected for many years with a difficult
to detect PNRSV isolate, without the expression of symptoms. In all these cases, the mild or
nonsymptomatic isolate is serologically differentiable from the more severe isolate and the severe
isolates appear to be very similar to the PNRSV-hop isolate described by Dr. C.B. Skotland. These are
only preliminary observations and more effort needs to be made to identify PNRSV/ApMV isolates
which produce few if any symptoms in infected plants.
How can we be certain that cross-protection occurs in hops? Virus surveys, examinations of ilarvirus
infected plants, and reports in the literature indicate that mixed infections of PNRSV and ApMV do not
occur despite infected plants being grown in close proximity to each other. Secondly, in the 'Nugget'
yard referred to above,the symptomatic and nonsymptomatic virus strains were clearly discernable with
no evidence of mixed infections. And lastly, symptoms of PNRSV are rarely observed in 'Cluster' hops
originating from the virus-tested program, despite many years removal from the program; these hops
are infected with a mild or nonsymptomatic strain of PNRSV. Almost certainly cross-protection occurs
naturally in hop and it seems quite probable that it could be used to control infection of hop plants by
severe strains of PNRSV/ApMV. Ultimately, the question becomes whether cross-protection provides
a level of protection needed in the hop industry today and the WHC commissioners, as growers, are
in a far better position to answer that question than I. Planting of virus-free hop rootstock will remain
the best PNRSV/ApMV control method, providing that certain conditions can be met in their planting.
These conditions include either planting in ground which has never been planted in hops before of
planting in ground in which ALL plants from earlier plantings have been removed. A complementary
virus control program based on cross-protection seems appropriate for those cases when planting of
virus-free rootstock seems inappropriate.
Objective 2 Subobjectives:
1. Identify PNRSV/ApMV isolates causing mild if any symptoms in hop.
These isolates must be serologically differentiable from severe isolates; 2. Infect several hop varieties
with each of the above nonsymptomatic isolates as well as a severe isolate; 3. Propagate virus-infected
plant materials and plant a test yard to examine the effects of the different isolates on various yield
parameters. This will continue for a number of years and must include at least one "Prunus year", a
season with environmental conditions particularly suitable for PNRSV/ApMV symptom expression; and
4. Simultaneously with Objective 3, test for cross-protection between the rpild isolates and other strains
which are serologically differentiable. Subobjective Procedures: 1. Serological differentiation of many
isolates has already been accomplished. In addition, a number of hop yards have been identified with
a high incidence of PNRSV but no history of PNRSV-related diseases. These include Cluster, Galena,
and Nugget hop yards. Rhizomes need to be collected form these yards. 2. Virus-free hops of each
variety will be infected by planting a number of virus-free rhizomes in a single pot containing a rhizome
infected with the desired PNRSV/ApMV isolate. Past experiments indicated 100% infection within 2
years and I suspect equally high rates after a single year. Four hop varieties would be used: Galena,
Cluster, Nugget, and Willamette. Beside being widely grown, these varieties have different genetic
backgrounds and we can test for hop variety by virus isolate interactions. 3. A hop yard would be
planted with softwood cuttings made from the infected plants. In the field test. I anticipate 4 varieties
KLEIN
Page 23
by five virus treatments (virus-free, severe PNRSV, and three nonsymptomatic isolates). To minimize
virus spread between treatments, plantings would be made on 14-ft centers. Plots would be evaluated
yearly for vigor, yield, and alpha acid content. Essential oil profiles would also be evaluated when
appropriate. 4. Attempts will be made to infect plants infected with nonsymptomatic isolates with other
serologically differentiable isolates. This will be done by planting hop roots infected with different virus
isolates in a single pot. We will also attempt graft inoculations. Plants will be tested annually by
serology to detect mixed infections or changes in isolate identity.
TIME FRAME:
This is a long-term project with interconnected objectives. The exact duration will largely depend on
Objective 3. The test plot must be maintained for at least three years after the initial planting and would
need at least one "Prunus year" in which we would observe severe losses in all varieties with the
severe PNRSV isolate. An optimistic time frame is:
Objective
Objective
Objective
Objective
1:
2:
3:
4:
to be accomplished in 1994
to be accomplished in 1995
hop yard to be planted in 1996, evaluation to begin in 1997 and end in 1999 (?)
begin in 1996 or 1997, continue through 1998-99.
Objective 3 depends on the availability of suitable compounds. IfAnn George's sources at IR-4 and EPA
indicate that there is no prejudice against a registration for Bravo, that will be started this spring.
Otherwise, we will have to determine if there is another compound acceptable to all parties, including
brewers.
Objective 4 is broad and must be addressed on several levels. Many hop yards with poor vigor have
been identified. In addition to poor vigor, the crowns exhibit excessive amounts of "bark" and,
frequently, the center of the crown appears dead and new growth occurs in areas peripheral to the
original plant. The varieties involved include 'Willamette', 'Tettnang', 'Galena', and 'Chinook'. Soil
taken from these yards will be planted with healthy rootstock in microplots in an attempt to induce
similar symptoms in healthy plants; some soil will be steam-sterilized to eliminate biological agents and
will serve as a control. Samples will be submitted to Dr. Santo for nematode analysis. Past analyses
for virus infection have not revealed unique virus infections but leaf samples will be examined by
electron microscopy for previously undetected pathogens. We will also begin to examine the effects
of virus infection on crown growth. Very preliminary observations in our collection of PNRSV/ApMV
isolates has indicated some severe abnormalities in virus-infected plants, but we have lacked the
healthy controls necessary to make conclusions.
Objective 5. Our supplies of antisera and other diagnostic reagents is low and some time and effort
must be invested in making new antisera to viruses. This will be accomplished during the next year.
Past efforts in serological diagnosis of fungal diseases, particularly Verticillium wilt, will be continued.
Recent results indicate that our antisera will differentiate Verticillium isolates from maple, alfalfa, potato,
and hop. Prediction is difficult but I expect that this research will need to be continued for two to three
more years.
Objective 6 is an ongoing project. We are currently screening over 20 advanced breeding selections for
their response to downy mildew and will expand the test plot as new materials become available. We
will also begin testing these materials for their response to heptachlor soil residues in the spring 1995.
KLEIN
Page 24
Table 1.
Incidence of PNRSV, ApMV, HMV, HLV, and AHLV viruses in hop in WA, ID, and OR.
Number of hop yards sampled for each variety is listed parenthetically after the variety.
lllllilliiililill
^^^^^^^P |||i|il||l;|||||||;|i||||||:|||| ^^^^^B llllllllll
§ililiillllllll
iliili^H^llliii
Cluster (9)
88.3c*
Galena (8)
41.9ab
Chinook (5)
45.0b
Oa
0.6a
Oa
90.6d
92.2a
96.1d
19.4b
95.6a
91.3cd
100.0a
89.0cd
Oa
Oregon
Nugget (13)
31.9ab
Willamette (17)
89.1c
0.8a
Oa
18.1b
84.0a
58.1a
43.9c
94.7a
72.4a
Washington
Galena (30)
51.8ab
1.3a
19.6b
92.2a
68.7ab
Cluster (19)
87.9c
2.4a
83.7d
94.5a
82.1bc
Willamette (18)
29.4a
0.6a
38.1bc
88.9a
70.3b
Nugget (13)
46.5b
1.9a
26.9b
87.3a
49.2a
Chinook (10)
27.5a
1.0a
1.5a
97.5a
99.Od
Cascade (9)
69.4bc
0.6a
45.6c
87.2a
72.2b
Tettnang (9)
20.0a
1.1a
37.8bc
95.6d
76.1b
i^liiiiiiSlllilllllilli ||||||l|l|l;iiii|i5|||||||l||||il|l|||;;;i;| |§|||l||l|||§ isiiiiiiiiiiii llllllllllll
*
Within columns, means followed by the same letters are not significantly different at the 0.05 probability level as
determined by the Kolmogorov-Smirnov test.
Table 2.
The average amount of time (days) required for each step of tissue culture and total
average amount of time require for plantlet regeneration for two groups of 15 hop
clones. Two clones in Group A and 10 clones in Group B have 'Brewer's Gold' in their
pedigrees.
Total
Shoots
Roots
Establishment
80.3
14.7
42.7
22.9
Range
64-93
9-32
26-59
16-31
Average
124.5
17.1
78.7
28.7
109-140
10-27
63-90
21-37
Group
Group A
Group B
Average
Range
KLEIN
Page 25
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A
•
1
Year
HLV
1994
i
a
HMV
/,* AHLV
,
1
1995
-
1990
3
e
-
-
HLV
AHLV
HMV
•
a
•
Year
1
1994
1
1
•
•
1993
1
1
-
-
1995
-
-
Unit.
carlaviruses in a plot of 'Nugget' hops.
FIGS. 3B AND 3C indicate rates of spread of 3
and Skotland.
FIG. 3A Prepared from data collected by Kenny
Roza
Spread of carlaviruses in plots at the
3B
1992
0< K=—
50
100
FIG.
FIG. 3
Z
150
200
250
300
JOU
PROJECT NO.:
8198
TITLE:
Water Management and Chemigation of Subsurface Drip-Irrigated Hops
PERSONNEL:
Principal Investigator: R.G. Evans, Assoc. Agricultural Engineer, WSU-Prosser
M.W. Kroeger, Lead Engineering Tech, WSU-Prosser
M.O. Mahan, Agricultural Research Tech III, WSU-Prosser
Cooperators:
W.W. Cone, Entomologist, WSU-Prosser
R.G. Stevens, Ext. Soil Scientist, WSU-Prosser
INTRODUCTION:
It is estimated that about 3500 acres of buried (subsurface) drip irrigation (SDI) are currently installed
on hops in the Yakima Valley. Current trends indicate that installation of SDI on hops will rapidly
increase in the near future. Under proper management, these "environmentally-friendly" irrigation
systems offer several advantages to growers because of their potential for: 1) eliminating irrigation
induced soil erosion; 2) saving water through very efficient water applications; 3) easy and inexpensive
automation which reduces labor costs and improves management flexibility; 4) better weed control
without chemicals since the soil surface remains dry; 5) minimizing soil water deficits for improved
yields; 6) efficient application of fertilizers and plant-systemic pesticides; and, 7) reducing pesticide
exposures for workers.
JUSTIFICATION
Crop water use, fertility requirements and other plant responses may be substantially different from
historical expectations under high frequency SDI. In addition, many of the new hop varieties, with very
diverse growth habits, are being grown under SDI systems. Another specific grower interest is the
increased efficacy and a corresponding reduction in use of chemicals (eg. aphicides and fertilizers)
applied through the systems and water management to minimize their potential for movement toward
the groundwater. Answers are urgently needed by hop growers interested in utilizing SDI technology.
OBJECTIVES:
This multidisciplinary project is designed to develop criteria for SDI system design and appropriate water
management practices for SDI chemigation of hops. Specific objectives for this long-term project are:
1.
2.
Investigate SDI as a means of applying selected systemic aphicides on hops.
Evaluate water application strategies for SDI of hops that minimize chemical movement towards
the groundwater.
3.
Assess seasonal water use patterns by four varieties of hops in the Yakima Valley irrigated by
SDI.
4.
Assess root intrusion problems for buried "Netafim" and "Geoflow* trickle tubing in the border
areas of the test site.
PROGRESS FOR 1994:
A complex subsurface drip irrigation system was installed in an existing 2.58-acre hop yard (planted
1991) at WSU-Prosser in the spring of 1992. Each of the four main varieties ('Mt. Hood', 'Liberty',
'Willamette', and 'Chinook') were subdivided into 12 plots. Each plot was five rows wide by seven hills
long, and each had a separate irrigation system joined through a valve manifold at the top of the field
EVANS
Page 28
with the other eleven plots within each variety. The 'L8' borders were divided into four sub-blocks for
a root-intrusion study (2 Geoflow and 2 Netafim).
Aphicides
Systemic pesticides were injected at the valve cluster at the top of each block only once
on June 23. Some plots were scheduled to be retreated, but the aphid pressure was so low that these
treatments were not applied (mites, however, were a problem). Borders did not receive any pesticide
treatments. Chemicals applied were:
Treatments (equivalent lbs Al/A) in 1994 for aphicide study.
Date
ADM
ADM
ADM
DIM
DIM
DiS
DiS
DiS
6/23
.05
.125
0.25
1.0
2.0
1.0
1.5
2.0
ADM = ADMIRE; DIM = Dimethoate; DiS = DiSyston.
Field counts of aphids and mites on leaves were made about two times/week starting the second week
of June. Leaf sampling and brushing started the first week of July. Dried cone samples from the
Disyston plot series were be taken at harvest and eventually analyzed for residues. The efficacy results
of the aphicide portion of the study will be included under Dr. Cone's reports.
Irrigation
Irrigation level was also not a treatment. Due to a very undependable water supply (it
would sometimes disappear for hours at widely varying intervals), we were unable to utilize the
automatic control system. Consequently, we scheduled daily irrigations based on climatic data and
tensiometer readings. Irrigations were pulsed on and off about four times a day. Tensiometers were
monitored and irrigations adjusted to maintain soil matrix potentials at approximately 20 cb at a 15-inch
depth about 6 inches directly to the side of an emitter. Neutron probe access tubes for soil water
monitoring were also read weekly throughout the season. Total water application amounts and
durations were monitored with flow meters. Sodium hypochlorite (chlorine source) was injected
throughout the entire irrigation system (plots plus all borders) for bacterial and algal control on a weekly
basis. Estimated crop water use
for 1994 was: 'Mt. Hood', 18.7 inches; 'Liberty', 18.5 inches;
'Willamette', 15.7 inches; and, 'Chinook', 18.5 inches.
Fertilizer
Fertilizers were not a treatment and were uniformly applied (148 lbs/A N as CAN-17,
40 lbs/A P as phosphoric acid) through the entire system from early June until mid-August. Potassium
(25 lbs Al/A K) was applied after the N and P in August-September. Proportional, water-powered
injectors were used so that fertilizers were injected at a preset concentration each time the irrigation
system operated.
Root Intrusion In order to address some grower concerns, root intrusion on subsurface Netafim with
Geoflow (Treflan™ embedded in the emitters) tubing in the outside L8 border plant rows were compared.
Flow rates were carefully monitored for the onset of plugging, if any. Sections of these tubes were
excavated and carefully examined for root intrusion in late October 1993. Rooting distributions were
observed, and no plugging was found in either type of tubing. This process was repeated in 1 994, and
the removed tubing is being examined and tested for root intrusion at this time.
PROPOSED RESEARCH FOR 1995:
OBJECTIVES AND % ESTIMATED COST BREAKDOWN:
1.
Investigate SDI as a means of applying selected systemic aphicides on hops. (75%)
2.
Evaluate water application strategies for SDI of hops that minimize chemical movement towards
the groundwater. (10%)
EVANS
Page 29
3.
Assess seasonal water use patterns by four varieties of hops in the Yakima Valley irrigated by
SDI. (10%)
4.
Assess root intrusion problems for buried "Netafim" and "Geoflow" trickle tubing in the border
areas of the test site. (5%)
TIME FRAME:
It is anticipated that this project will be on-going for several years because of: 1) the need to develop
data required for registration of existing aphicides as well as any new, promising chemicals that become
available in the future; and 2) the continued increase in the use of subsurface drip by the hop industry
in the Yakima Valley. Objective 4 is probably the only "short-term" and will probably be concluded in
the next one to two years.
PROCEDURE:
The 1995 program will be a continuation of the 1994 efforts. No new directions are anticipated.
Irrigation and fertility will not be treatments. The first aphicide treatments will begin prior to aphid
migration (late May-early June) in 1995. Subsequent injections will be made based on weekly leaf
counts of aphid populations in each plot. Data will include: 1) counts of mites, aphids, mite eggs and
predators; 2) leaf samples for chemical residue analyses; and, 3) cone samples for residue analysis.
Fertilizers will be uniformly applied in the irrigation water starting in mid-May at about 125 lbs/A N and
25 lbs/A of P (about a 20-ppm constant injection of N except when P is injected at three or four
discrete times) until just prior to harvest. K will be injected at one time (about 25 lbs/A in early August.
Water use data (based on soil water data) for each variety will be correlated with the environmental
conditions measured at the WSU-Prosser Headquarters PAWS weather station. Sections of emitter lines
in each of the four border sub-blocks will be excavated and examined for root intrusion after the 1995
harvest. This will require removal and detailed examination of about three sections approximately 10
feet long from each treatment. Removed sections will be replaced with new tubing of the same type.
EVANS
Pa§e 30
PROJECT NO.:
6805
| ^^ WQR|( ^ mj supp0RTED gy WHC
TITLETITLE.
Weed Control in Hops
!, ™K
SUBMITTED AS A
cotfRT£SVB^T
JQ ^IS m[}sm
PERSONNEL:
Project Leader:
R. Parker, Extension Weed Scientist, WSU-Prosser
R. Baker, Agricultural Research Tech I, WSU-Prosser (.50 FTE)
OBJECTIVES:
1.
Screen herbicides for hop tolerance that possibly can be used for residual weed control.
2.
Screen contact herbicides and/or desiccants for hop tolerance, sucker control, and weed control.
3.
Screen candidate postemergence herbicides for hop tolerance that may be used for weed control
during the growing season and control of problem weeds.
4.
Determine hop tolerance to clopyralid residues in the soil.
5.
Determine baby hop variety tolerance to preemergence applications of oryzalin.
PROGRESS:
Twenty herbicides and/or desiccants, some at several rates and in combination, or with different
surfactants and carriers, were evaluated in eight experiments on hops grown in WSU-Prosser yards or
in the greenhouse. In addition three IR-4 field residue trials were conducted. All the products that
appeared promising from the 1993 trials, plus any that were requested by the industry or
manufacturers, were evaluated in 1994. In these tests, hops appeared to be tolerant to all the
herbicides tested when applied during the dormant season (Table 1), applied as desiccants (Tables 2
and 3), and all postemergence to the crop (Table 4). All trials will again be evaluated during the spring
of 1995 to determine if any residual effects remain from the 1994 treatments. An oryzalin (Surflan™)
tolerance study on seven varieties of newly planted hops was also conducted in the field (Table 5).
Dormant Application for Residual Weed Control
Hops appear to be tolerant to all the herbicides
evaluated for residual weed control (Table 1). The dominant weed in this trial was common
lambsquarters. To incorporate the herbicides into the soil, a sprinkler system was set up because of a
lack of rainfall after application. This trial will be repeated during the spring of 1995 and will include
any other herbicides that may show promise for future use. Kochia will be overseeded in the plot area
to determine effectiveness on that weed. Surflan was applied at two rates, the anticipated use rate and
twice the use rate, immediately after planting seven hop varieties to determine their tolerance to the
herbicide (Table 5). Surflan will probably not be registered for use on baby hops. The herbicide was also
included in the IR-4 program during 1994 on established hops. Simazine™ or Princep™ will not be
included in the 1995 trials and will not be included in further trials until the product is through the
reregistration process.
Sucker Control
Hops were tolerant to all the desiccants applied. The data from the sucker
control trials are presented in Tables 2 and 3. In trying to enhance desiccating properties of
Gramoxone™ and Des-I-Cate™, both desiccant trials contained treatments where liquid nitrogen (Uran
32) was compared to water as the herbicide carrier. Indications are liquid nitrogen may enhance
Gramoxone activity when applied later in the season. This study will be repeated in 1995 to confirm
the results. We also evaluated Surefire™, a mixture of paraquat plus diuron against Gramoxone. Both
products were applied at the equivalent paraquat rates. There were no significant differences between
the two products (Tables 2 and 3). Gramoxone and Surefire effectively burned down the weeds present
in the treated areas. The most promising herbicide (UBI C-4243) for desiccation and weed control
PARKER
Page 31
evaluated in previous trials was dropped from the program in 1994 because of lack of interest by the
manufacturer.
Postemergence to the Crop Applications for Control of Problem Weeds
Results of this experiment
with broadleaf herbicides can be found in Table 4. None of the herbicides tested caused symptoms on
to the foliage growing above that contacted during the spraying operation and any phytotoxicity
showing on the crowns was temporary. This trial included two rates of 2,4-D (Weedar 64™), clopyralid
(Stinger™), pyridate (Lentagran™) with and without a surfactant, and a combination of 2,4-D +
clopyralid. The surfactant addition did not increase Lentagran control of the weeds when compared to
the 1993 trials. The grass herbicides evaluated at various rates were clethodim (Select), sethoxydim
(Poast) and two formulations of fluazifop (Fusilade and Fusilade 2000). No grasses were present in the
study, thus the data is not presented. No injury was observed on the hops.
Baby Hop Bioassay Study
Considerable mint acreage inWashington has been treated over the past
few years with clopyralid (tradename Stinger). Spent mint hay is often spread back onto fields and
incorporated into the soil and that which has been treated with Stinger has resulted in injury to some
crops. This greenhouse study was initiated to determine if the clopyralid in mint slugs would be
detrimental to hop growth if incorporated in hop yards. The following amounts of herbicide was mixed
with greenhouse soil and placed in greenhouse pots. The labeled rate of Stinger on mint is 0.125 to
0.375 lb acid equivalent/A (1/3 to 1 pint).
Amount
in Sorl
Approximate Equivalent Amount/A in Top 12"
"~
Pound Acid Equivalent
Pints of Stinger
0.05 ppm
0.2
0.533
0.025 ppm
0.1
0.267
0.0125 ppm
0.05
0.133
0.00625 ppm
0.025
0.067
0
0
0
Roots were then planted and allowed to grow in the soil for six weeks. Plants were checked daily for
symptoms. No visible symptoms were observed at any concentration of clopyralid in the soil. This part
of the study was then followed up by planting roots in soil that was mixed with slugs from mint that
was treated with Stinger. Again no symptoms were observed on the hops.
PROPOSED RESEARCH FOR 1995:
Multiple tillage is the primary method of weed control in hops. Particularly with furrow irrigation, tillage
has contributed greatly to soil erosion. Also, tillage does not control the weeds growing with the hop
crop crown. Two herbicides are currently labeled for use in hops, trifluralin (Treflan) and norflurazon
(Solicam) for residual weed control. Treflan has to be mechanically incorporated into the soil, can delay
emergence of the crop in the spring, and is not effective on some weeds. Solicam also has some
limitations in controlling some weeds common in hop yards. Oryzalin (Surflan) is in the registration
process. Two or three manufacturers have expressed interest in evaluating their products in hops and
are willing to add the crop to their existing labels. To control perennial weeds, both 2,4-D and
glyphosate (Roundup) are in the registration process. Roundup will be used as a spot treatment since
it will also kill hops if sprayed on them. 2,4-D can be sprayed over the hop crown but will not control
certain broadleaf weeds. Other herbicides are being evaluated for use in hops. Paraquat (Gramoxone)
is registered for sucker control and burning back weeds and endothall (Des-I-Cate) is registered for
sucker control. Paraquat may cause injury to some varieties and effectiveness appears dependent on
hop variety and carrier volume. Endothall will not control weeds thus is limited in its effectiveness.
PARKER
Page 32
Oxyfluorfen) (Goal) is in the registration process for early season sucker control, but it is not efficacious
later in the season. Other promising chemicals that may have utility in hops for controlling sucker
growth are being tested.
OBJECTIVES:
1.
2.
Continue to screen promising candidate herbicides for residual weed control and crop tolerance
(1995) and attempt to get the most promising one(s) in the registration process.
Screen candidate contact herbicides for sucker control and crop tolerance (1995) and attempt to
get the most promising one(s) in the registration process.
3.
Evaluate candidate postemergence herbicides for weed control during the growing season and
attempt to get the most promising one(s) in the registration process.
PROCEDURE:
1.
Evaluate candidate herbicides applied in the spring and/or fall on established hops for residual
weed control and crop tolerance.
2.
Evaluate candidate herbicides in the spring before and/or after stringing to determine weed and/or
sucker control and crop tolerance.
3.
Work with chemical industry directly or through IR-4 after efficacy and crop tolerances are
determined to obtain hop registrations.
PARKER
Page 33
Table 1.
Weed control and crop injury from spring applied herbicides. Applied March 28, 1994.
Paraquat at 0.47 lb Al/A applied with all treatments.
Rate
Treatment
lbs At/A
Lambsquarter
Control
Visual
Crop Injury
Kerb
1.5
56.7c
0
Kerb
3.0
59.3bc
0
Solicam
1.0
66.7abc
0
Solicam
2.0
88.3ab
0
Prowl
1.0
93.3a
0
Prowl
2.0
97.7a
0
Surflan
2.0
83.3abc
0
Surflan
4.0
90.0a
0
Surflan
6.0
97.0a
0
Goal
0.5
92.0a
0
Goal +
0.5
98.0a
0
Surflan
4.0
Devrinol
4.0
66.7abc
0
Princep
1.0
96.7a
0
98.0a
0
98.0a
0
Od
0
Princep +
0.5
Surflan
2.0
Princep +
0.5
Prowl
1.0
CONTROL
PARKER
—
Page 34
Table 2.
Percent exposed foliage desiccation applied on May 12 prior to training.
Percent Desiccation
Carrier
(48.5 GPA\
WATER
URAN 32
Treatment
Rate/Acre
May 16
May 23
Gramoxone +
0.78 lb ai
51.7
68.3
Ortho X-77
0.25%v/v
Gramoxone +
0.78 lb ai
68.3
68.3
Ortho X-77
0.25 %v/v
63.3
70.0
Surefire +
1.125 lb ai
Ortho X-77
0.25%v/v
Dow General
0.625 lb ai
71.7
66.7
WATER
Des-I-Cate
1.0 1b ai
63.3
76.7
URAN 32
Des-I-Cate
1.0 lb ai
75.0
73.3
WATER
Goal
0.5 Ibai
68.3
75.0
78.3
75.0
81.7
80.0
70.0
70.0
75.0
73.3
WATER
WATER +
WATER
URAN 32
WATER
WATER
Diesel
+
Ag-98
0.25% v/v
Gramoxone +
0.78 lb ai
Des-I-Cate +
0.52 lb ai
Ortho X-77
0.25% v/v
Gramoxone +
0.78 lb ai
Des-I-Cate +
0.52 lb ai
Ortho X-77
0.25% v/v
Gramoxone +
0.78 lb ai
Omite +
1.5 lb ai
Ortho X-77
0.25% v/v
Enquik
15 gal
0
CONTROL
LSD (0.05)
PARKER
12.9
0
10.2
Page 35
Table 3.
Hop crown burnback with various herbicides used as desiccants applied on July 22
after training.
Percent Desiccation
Carrier
August 12
Treatment
RateiAcre
July 21
Gramoxone + Ortho
0.78 lb ai
20.0
30.0
X-77
0.25%v/v
Gramoxone + Ortho
0.78 lb ai
63.3
60.0
X-77
0.25 %v/v
Surefire +
1.125 lb ai
36.7
58.3
Ortho X-77
0.25 %v/v
WATER + Diesel
Dow General
0.625 lb ai
73.3
56.7
WATER
Des-I-Cate
1.0 lb ai
66.7
50.0
URAN 32
Des-I-Cate
1.0 1b ai
73.3
58.3
WATER
Gramoxone +
0.78 lb ai
73.3
56.7
Des-I-Cate
0.52 lb ai
Ortho X-77
0.25% v/v
Gramoxone +
0.78 lb ai
76.7
53.3
56.7
36.7
(48.5 <3PAr
WATER
URAN 32
WATER
URAN 32
Des-I-Cate
0.52 lb ai
Ortho X-77
0.25% v/v
WATER
Enquik
15 gal
WATER
F-6285
0.25 lb ai
WATER
F-6285
0.5 lb ai
WATER
DeFol 6
WATER
+
6.0
No-Foam +
2qt.
SURpHTAC
0.5% v/v
DeFol 6
9.0
+
No-Foam +
2qt.
SURpHTAC
0.5% v/v
0
33.3
43.3
0
CONTROL
LSD (0.05)
PARKER
3.3
10.8
3.3
0
36.7
46.7
0
26.1
Page 36
Table 4.
Pigweed and common lambsquarters control and hop injury resulting from herbicide
applied over crowns.
Percent Injury
Percent Control
Lambsquarters
Pigweed
August 12
September 6
Herbicide
Rate/Acre
Stinger
0.125 lb ae
60.0 b
50.0 b
0.0 b
0
Stinger
0.25 lb ae
85.0 ab
90.0 a
0.3 b
0
Weedar 64
0.5 lb ae
100.0 a
100.0 a
4.3 ab
0
Weedar 64
1.0 lb ae
100.0 a
100.0 a
4.0
0
100.0 a
100.0 a
3.7 ab
0
ab
Stinger +
0.125 lb ae
Weedar 64
0.5 lb ae
Lentagran
0.9 lb ai
100.0 a
96.7 a
3.7 ab
0
Lentagran +
0.9 Ibai
93.3 a
86.7 a
3.7 a
0
Ortho X-77
0.25% v/v
Lentagran
1.8 lb ai
100.0 a
100.0 a
7.0 a
0
Lentagran +
1.8 lb ai
100.0 a
100.0 a
6.0 a
0
Ortho X-77
0.25% v/v
0.0 a
0.0 c
0.0 b
o
Control
Means followed by the same letter do not differ at the 5% level based on Duncan's Multiple Range Test at the 5% level of
significance. Groups of letters (a-e) suggest that all letters (abcde) are associated with that particular mean.
Table 5.
Dry weight in grams of the above ground growth of seven hop varieties
90 days after planting from roots and treated with Surflan immediately
following planting. Surflan watered into the soil with approximately 1/2
inch of overhead moisture within 24 hours of application.
U.S.
Rate
Treatment
Jb At/A
Pearle
Wit. Hood
Cluster
Galena
Willamette
Nugget
Tettrwnger
36.370 ab
46.340 a
38.645 a
31.564 a
68.119 a
36.910 a
50.740 a
Control
0
Surflan
4.0
34.144 b
41.088 a
41.406 a
31.102 a
36.097 tr
39.755 a
59.769 a
Surflan
8.0
41.963 a
46.650 a
50.452 a
32.963 a
65.756 a
56.082 a
41.150 a
Means followed by the same letter do not differ at the 5% level based on Duncan's Multiple Range Test at the 5% level of
significance. Groups of letters (a-e) suggest that all letters (abcde) are associated with that particular mean.
PARKER
Page 37
PROJECT NO.:
TITLE:
1867
Investigation of the Effect of Rate and Time of Nitrogen Application on Yield
and Quality of Hops.
PERSONNEL:
Project Leader:
R.G. Stevens, Extension Soil Scientist, WSU-Prosser
R.G. Evans, Assoc. Agricultural Engineer, WSU-Prosser
S.T. Kenny, Assoc. Agronomist, WSU-Prosser
V. Prest, Agricultural Research Tech III, WSU-Prosser
OBJECTIVES:
The primary object of this project is to develop management guidelines (BMPs) for nutrient additions
through buried drip irrigation systems. These BMPs will encourage optimum nutrient use while
maintaining optimum hop yield and quality and at the same time minimize nitrogen (N) loss to
groundwater. Specific objectives are:
1.
To determine the effect of N rate and timing on hop yields and quality, as well as biomass and
N distribution.
2.
To develop a petiole leaf analysis data base to be used as a tool in N management under drip
irrigation systems.
3.
To estimate N use efficiency under buried drip irrigation and reduction for potential nitrate
leaching to groundwater.
SUMMARY OF 1994 RESEARCH:
The 1994 results reemphasize the variable nature of both hop yield and petiole nitrate levels among
years. Climatic conditions in 1993 and 1994 were very different and can explain many of the
differences found. These results underscore the need for several years data to develop management
guidelines. No significant differences were found between the plot receiving mostly nitrate as CAN-17
and the plot receiving mostly ammonium as UAN. These results suggest that the nitrogen in the urea
and ammonium form in the UAN is available to the plants. This probably indicates that these nitrogen
sources are being converted to nitrate in the drip zone. Results of analysis of soil samples taken near
the emitters will help determine nitrification rates. The 12 lbs N/week rate (total 103 lbs N/A, Treatment
5) was not adequate to support petiole nitrate levels at a needed level or to produce optimum yield. The
other N treatments appeared to support adequate petiole nitrate levels and produce optimum yields for
this particular year. There is no explanation of the reduced yield in the grower treatment plot. Petiole
levels remained high throughout the season and N uptake was high. Significantly lower petiole nitrate
in the low N treatment occurred in late June and late July, suggesting these as critical periods. This
would be supported by Christensen's work in Oregon indicating that rapid accumulation of dry matter
is completed by mid-July and that N is taken up in advance of dry matter production. Therefore, it is
important to determine the period of critical N uptake and what levels of petiole nitrate are needed to
support this uptake. The 1995 treatments will be designed to help determine critical timing and petiole
nitrate levels. It is important to remember that the effectiveness of N applications is highly dependent
upon irrigation management. Excessive applications of water may lead to movement of N out of the
active uptake area, leave that N stranded out of the rooting zone or available to leach out of the root
zone towards the groundwater. Recovery rates, as suggested by total N uptake, demonstrate that N
efficiency could probably be improved with better water management. Additional analysis of irrigation
data and soil samples is needed before final conclusions can be made from these results.
STEVENS
Page 38
PROGRESS:
N Fertilizer Trial With Drip Irrigation The 1994 trial is a continuation of plots established in 1993. The
1993 N rate trials were established in a two-year-old 'Galena' yard near Mabton. The yard was
established on a 3.5 X 12 ft spacing with buried drip irrigation in an area that had not previously been
used for hop production. Sprinkler irrigation was used at establishment and to establish cover crops.
Soil type is a Hezel loamy fine sand. The grower measured 45 lbs N/A in the top foot prior to the 1993
growing season. Irrigation scheduling as well as irrigations were done bythe grower and was the same
on all plots. N treatments were imposed upon his irrigation schedule. Irrigation rates were monitored
for each treatment. Individual plots were established by altering the growers buried drip system to allow
application of different rates of N to individual plots. Each plot was four rows wide and 116 feet long.
Five sets of treatment plots with four replications were established. One treatment was the growers
application schedule and the other four treatments were applied by the research team.
The five N treatments in 1994 are shown in Table 1. Treatment 1 was the grower's N application rate.
Grower plots received a total of 179 lbs N/A during the growing season. Grower N application was
heaviest during the early season and decreased towards harvest. Experimental N rates given in Table
1 were designed to determine the effect of early-season N application on the hop plants. Treatments
2 and 3 were designed to apply 15 lbs N/week from June 1 through August 1 and the 2 lbs N/wk
through August. Low petiole nitrate values in 1993 brought about a question as to the availability of
ammonium N under buried drip conditions. Therefore, CAN-17, a predominantly nitrate source, was
used in Treatment 2 to compare with the urea ammonium nitrate (UAN) source used in all other plots.
The UAN source had potassium added; the potassium was not added with the CAN-17 treatment.
Treatment 4 represented an increase in the proportion of N added early in the season. Nitrogen was
added at a rate of 18 lbs N/wk June 1 through July 15, at 4 lbs N/wk July 15 through August 1, and
2 lbs N/wk through August. Treatment 5 represented an effort to have at least one treatment where
limited N stress occurred. In Treatment 5, N was applied at 12 lbs N/wk from June 1 through August
1 and at 2 lbs N/wk through August. Grower N applications were made whenever irrigation was
conducted. The other four applications were made during one irrigation cycle each day, Monday
through Friday. The same N sources were used as the grower, except for Treatment 2 where CAN-17
was used. Accumulative N applications over the season are shown in Figure 1. All plots received 20
to 25 lbs P205/A. Potassium applications varied with N level, the plots received 30 to 40 lbs K20/A,
except for Treatment 2 which received no potassium. Standard additions of chlorine and acid were
made to insure that drip emitters remained open. Some variability in residual soil nitrate would be
expected among the treatments. However, since the 1993 N applications ranged from 94 to 135 lbs
N/A, residual nitrate differences would not be expected to be high. Sprinkler irrigation across the plots
to establish a cover crop would have moved the N from the pattern established around the emitters.
Yield and N Uptake
Ten hills from each of the center two rows were harvested to determine total
vine dry matter production, cone yield and N uptake, as well as cone quality. Standard harvest and
analysis procedures were followed. Yield and N uptake data are presented in Table 2. An average vine
dry matter yield of 3,149 lbs/a was obtained in 1994. This was significantly below the average of
3,857 lbs/a in 1993. This difference in vegetative production was visible and could be seen throughout
the yard. This decrease in total vine production appeared to be related to growing conditions and not
treatments. Treatment 5, which had the lowest early rate of N application (12 lbs N/wk) and lowest
total N application (103 lbs N/A) had significantly less vine dry matter production, indicating inadequate
N supply. No significant difference was found among the other treatments despite differences in rate
and total N application. Nitrogen uptake in the vines averaged 48.4 lbs N/A. Nitrogen uptake was
significantly less for treatment 5 which received the least total N. Uptake varied across the other
treatments, but within a 12 lbs N/A range. Overall cone yield averaged 1,337 lbs/A on a dry weight
basis (1,444 lbs/A at 8% moisture). This was down significantly from the average yield of 2,282 lbs/a
in 1993. This reduction in yield was seen across this yard and not just in the plot area. Significant
differences in cone yield were seen among the treatments; however, these differences did not exactly
correlate to rate or amount of N applied. Although the grower treatment had the highest N content, it
had the same cone yield as the low N treatment (5). There was no significant difference in yield or N
STEVENS
Page 39
content among the other treatments. These results indicate that approximately 125 lbs N/A was
adequate for yield potential under these conditions. No explanation is available for the somewhat
reduced yield at the high N rate in the grower treatment. Total N uptake in the cones ranged from 27
to 32 lbs N/A. Only the low Ntreatment (5) was significantly below the other treatments in N uptake.
Total N uptake by vines and cones ranged from 66 to 86 lbs N/A. Only Treatment 5, the low N
treatment, had significantly less N uptake. As in 1993, the alpha and beta acid levels of cones were
not significantly affected by the N treatments (Table 3.).
Petiole Nitrate Levels
Petiole samples were taken weekly beginning on June 22 in an effort to monitor
the plant's response to N applications. A total of 40 petioles were taken from each plot at each
sampling. Petioles were taken from fully expanded healthy leaves on the main stem at head height.
Towards the end of the season some leaves from lateral branches were used. Season-long average
petiole nitrate N values for the five treatments are given in Figure 2. Comparison of petiole values
between years must be done with an understanding of differences in growing season, but is necessary
if petiole values are to be used as a crop management tool. The first petiole sample on June 22, 1994
was significantly lower than the first sample in 1993, and may be related to differences in growth
stage, a decrease in stored N, or a decrease in residual soil nitrate. At this point we do not have
adequate information to determine the cause of this decrease. Although there are relatively large
differences in petiole nitrate levels between treatments on June 22, there were no statistically
significant differences. Petiole nitrate was highly variable across replications at this first sampling.
Petiole nitrate levels through July 1994 were in the same range as 1993 values. The marked increase
in petiole nitrate level on July 13 isn't explained by treatment effects. This kind of peak might be
explained by a change in growth rate brought about by climate conditions or changes in plant water
status. Through July, the grower treatment and the high Nrate (Treatment 4) were significantly higher
than the other treatments, indicating that maximum uptake was not occurring with the other three
rates. As petiole nitrate levels fell in August, the grower treatment remained statistically higher than
the other treatments. The 1994 levels for all treatments fell below values obtained in 1993. The lowest
Ntreatment (5) was significantly below the other treatments throughout August. The grower treatment,
which was still receiving significant N, also decreased in petiole nitrate level during August as N was
apparently allocated to cones. Recent work in Oregon by Christensen and Hart indicated that July
petiole samples must fall below 3,000 ppm nitrate before a decreased yield response is seen. Our data
seems to indicate a similar critical petiole level. Analysis of July 27th petioles for potassium showed
no difference in potassium level among treatments, and included the CAN-17 treatment which did not
receive any potassium additions.
PROPOSED RESEARCH FOR 1995:
OBJECTIVES:
The primary objective of this project is to develop management guidelines (BMPs) for nutrient additions
through buried drip irrigation systems. These BMPs will encourage optimum nutrient use while
maintaining hop yield and quality and at the same time minimize N loss to groundwater. Specific
objectives are:
1.
To determine the effect of N rate and timing on hop yields and quality, as well as biomass and
N distribution and to estimate N use efficiency under buried drip irrigation. ($7,720)
2.
To develop an initial petiole analysis database to be used as a tool in N management under drip
irrigation systems. ($2,000)
PROCEDURE:
The 1995 effort will be based on results from 1993 and 1994. Buried drip fertigation plots, established
in a 'Galena' hop yard near Mabton in 1993, will continue to be utilized. Five treatments, including the
growers fertilization schedule, were followed during 1994. Nitrogen treatments for 1995 will be
STEVENS
Pa§e 40
adjusted by applying a larger portion of N in one treatment early in the year. An additional year of
comparison of nitrate vs ammonium source will be included. Monitoring of water applications and
nutrient movement will be increased, to better determine plant availability of added N. Petiole N will
continue to be monitored to determine to relationship between N additions and plant response to N
uptake. This third yearof results will help explain the variation in petiole nitrate levels seen in 1993 and
1994.
Fall 94:
Complete 1994 lab analysis, data analysis, and reports
Determine residual soil N levels
Spring 95:
Determine desired treatments
Estimate available residual N
Summer 95:
Apply treatments and sample petioles
Take appropriate soil samples to monitor N
Harvest plots and conduct lab analysis
Fall 95:
Take year-end soil samples
Complete data analysis and write yearly report
Work with producer to remove plots from yard
Write final report of project and determine future direction
STEVENS
Page 41
Nitrogen application treatments at Mabton drip study, 1994.
Table 1.
Total
Treatment
Source
N lbs/A
Rate and Timing
11
UAN-K
179
100-300 ppm
August 30-40 ppm
CAN-17
127
1 5 lbs/w2 8/1
2 Ibs/W 9/1
1 5 lbs/w 8/1
128
UAN-K
2 lbs/w 9/1
18 lbs/w 7/15
126
UAN-K
4 lbs/w 8/1
2 lbs/w 9/1
12 lbs/w 8/1
103
UAN-K
2 lbs/w 9/1
Grower application
Lbs N applied/wk
The effect of N rate on yield, N uptake, and hop quality of the 1994 Mabton drip study.
Table 2.
1993 Values
Trash
Gone*
-
Dry
N
matter
Dry
uptake "
matter
N
Total
uptake
ttarit
Uptake
Alpha
Beta
Treatment
Stt/A1
%ti
Ktt/A
IbS/A1
%N
8»/A
SI lbs/A
1
3105ab2
1.78a
56a
1228b
2.41a
30ab
85a
14.22
8.94
2
3204a
1.50ab
48abc
1439ab
2.23ab
32a
80ab
13.48
8.54
3
3374a
1.62ab
55ab
1486a
2.11b
31ab
86a
14.11
8.67
4
3368a
1.34b
44bc
1308ab
2.28ab
30ab
79ab
13.86
8.46
5
2745b
1.47ab
39c
1228b
2.17b
27b
66b
14.28
8.63
(8%)
Oven-dry basis
Values in a given coimn followed by different letters are significantly different at the 5% level.
STEVENS
Page 42
C/J
2
H
W
^
^
160-
180
200
^
^
^
^
n>
^
^
/
Date
>^ «/ o>^ o/ ^ ^ ^ ^ of of
& * & # # ^ n* <* oN
/:Trt 4 ..*•Trt .5
(Treatment 2 CAN-17, Treatment 3 UAN-K)
Treatment 2 and 3 have same accumulative nitrogen applications.
^
^
*- Grower ."•: Trt 2 — Trt. 3
1994 Mabton Drip Study.
Figure 1. Accumulative nitrogen applications for
z
H
W
Effect of nitrogen rates on petiole nitrate
Date
measurements for 1994 Mabton Drip Study.
Figure 2.
PROJECT NO:
4415
TITLE:
Hop Cultivar Development, Physiology and Chemistry
PERSONNEL:
Project Leader:
S.T. Kenny, Assistant Agronomist, WSU-IAREC
B. Bienz, Research Technologist II, WSU-IAREC
V. Garza, Technical Farm Laborer, WSU-IAREC
M. Pillay, Post-Doctoral Research Associate, WSU-IAREC
T. Vasile, Laboratory Technician II, WSU-IAREC
OBJECTIVES:
The long-range goal of this project is to develop new pest-resistant, high-yield potential hop cultivars.
Immediate cultivar and germplasm development objectives are to identify selections with brewing
properties useful to brewers, identify genotypes with improved levels of resistance to hop downy
mildew, evaluate genotypes resistant to hop aphid, develop sets of restriction fragment length
polymorphism (RFLP) and randomly amplified polymorphic DNA (RAPD) markers in hop, and to describe
genetic relationships within the hop germplasm collection. Support research includes investigation of
chemical methods to identify factors important for hop quality.
ACCOMPLISHMENTS OF 1993 RESEARCH:
Sixty-nine selections were transferred from the seedling nursery to two-hill plots. The 1,439 plants
remaining in the seedling nursery were again surveyed for growth habit and cone samples from 336
plants were collected for analysis. The field trial designed to identify genotypes resistant to twospotted
spider mite was surveyed, but genotypes consistently resistant to twospotted spider mite were not
found. Additional genotypes resistant to hop aphid were not identified, but seedlings from two
additional families for resistance to hop aphid screening were established. Screening DNA from 24
genotypes with ribosomal DNA probes divided the genotypes into two groups: one containing primarily
American germplasm and the other with primarily European germplasm. An additional 150 hop nuclear
DNA probes were screened as RFLP probes, five uncovered polymorphisms. Thirty RAPD probes were
screened and two uncovered polymorphisms. Off-station trials of 8254-167 were monitored.
OBJECTIVES OF 1994 RESEARCH:
Select plants from the seedling nursery for desirable growth habit and brewing quality. Evaluate new
seedlings planted in 1993 for desirable growth habit and brewing quality. Make crosses for pest
resistance studies and brewing quality factors. Evaluate plants representing two families for resistance
to hop aphid. Screen hop germplasm with existing organellar DNA probes and other molecular probes
as available to describe genetic relationships within the hop germplasm collection. Evaluate RFLP and
RAPD probes by screening 100 new hop nuclear DNA clones and 60 new RAPD probes. Do brewing
quality analysis of hop samples from breeding and germplasm development activities. Continue
monitoring off-station trials.
ACCOMPLISHMENTS OF 1994 RESEARCH:
Twenty-two selections were transferred from the seedling nursery to two-hill plots. Cone samples were
taken from 411 seedlings. Samples from the remaining 500 plants were not taken due to poor growth
likely caused by a lack of water during the early growing season. Parents for a second cycle of selection
for hop plant resistance to hop aphid were selected. A series of 80 RAPD probes was screened against
a panel of hop DNAs representing 12 hop genotypes. Reliable polymorphisms were found with a few
probes. Screening with 120 hop nuclear DNA clones with several hop DNA digests did not uncover any
useful polymorphisms. Brewing quality analysis of samples from the 1993 and 1994 crop years were
completed. A summary of essential oil data lead to the finding that two groups of compounds (methyl
KENNY
Page 45
ketones and alcohol esters) appear to be directly and inversely associated with European aroma hops.
Off-station trials of Washington selection 8254-167 and USDA selections 21664, 21665, and 21666
were monitored.
KEYWORDS:
Hop breeding, germplasm development, hop aphid, molecular genetics, RFLP, RAPD, alpha-acid, hop
aroma, Tettnanger triploid, experimental cultivars (Washington 8254-167, USDA 21664, 21665,
21666).
PUBLICATIONS:
Kenny, S. and B. Bienz. 1994. Hop essential oil constituents associated with European aroma hops.
Abstr. Amer. Soc. Brew. Chem. Newsletter 54(2):26.
Kenny, S. and B. Bienz. 1994. Hop essential oil marker compounds in American hops. Abstr. Amer.
Soc. Brew. Chem. Newsletter 54(2):25-26.
Kenny, S.T. and M. Pillay. 1994. Inheritance of ribosomal DNA length repeats in hop. Agron. Abstr.
Amer. Soc. of Agron., Madison, Wl, p. 214.
Pillay, M. and S.T. Kenny. 1994. Segregating random amplified polymorphic DNAs (RAPDs) in hop.
Agron. Abstr. Amer. Soc. of Agron., Madison, Wl, p. 213-214.
Pillay, M and S.T. Kenny. 199_. Chloroplast DNA differences between cultivated hop, Humulus lupulus
and the related species H. japonicus. Accepted by Theoretical and Applied Genetics.
PROGRESS IN 1994:
Breeding and Germplasm Development We selected 22 plants from the seedling nursery based on data
from the 1992 and 1993 growing seasons. These were selected for potentially useful brewing qualities.
The selections were established from rhizome pieces planted in March. The yield and chemical analysis
of these selections are presented in Table 1. The list in Table 1 also includes selections reported last
year that were harvested again this year. When sufficient sample was available in 1993, a sample
stored for six months at room temperature was analyzed and the results are reported in Table 1. The
selections in Table 1 are primarily aroma types. The initial selections were made for a-acid levels
between 6 and 8% with cohumulone below 15%. Some selections with a-acid levels over 10% and
some with yff-acid levels over 9% are also present. No detrimental agronomic problems were observed.
Over 900 plants established in 1993 in the seedling nursery, representing 16 families and seed collected
by Dr. Klein in China, were examined. The goals of the crosses were to provide material for testing hop
resistance to hop downy mildew or hop aphid. Unfortunately, irrigation water was not available to this
field until the end of May. Although most plants survived, only about 400 were large enough to harvest
for cone samples. Since the material was too small during the part of the growing season useful for hop
downy mildew screening, no assessment of resistance or susceptibility to leaf infection by hop downy
mildew was done.
The two families designed to complete testing of the inheritance of hop plant resistance to hop aphid
were also established in the seedling nursery in 1993. These, too, were affected by lack of water, so
useful data from these plants was not possible. About 120 male and female plants with measured
resistance to hop aphid were established in new locations. These plants were screened for agronomic
characters and brewing quality. We identified plants to use as parents in a second cycle of crosses to
provide materials for selection for hop plant resistance to hop aphid.
Molecular Genetics During the past year, we increased our efforts to find RAPDs in hop. We have
tested 100 primers in at least 12 genotypes. We are still encountering difficulties in the repeatability
of our RAPD experiments. We examined the inheritance patterns observed with two RAPD probes in
KENNY
Page 46
four hop families. The observed frequencies of presence versus absence of a fragment in the progeny
followed the expected 1:1 or 3:1 ratios. We examined an additional 120 hop genomic DNA probes for
their ability to uncover RFLPs in hop. To date, we have found 3 useful RFLPs probes. We did uncover
an interesting RFLP in ribosomal DNA (rDNA). We found that there are three phenotypes for rDNA
repeat length: one which is common to all native European varieties in our collection, a second which
is common to all North American plants in our collection, and a third which is present in cultivars that
are hybrids between these two germplasm pools. We do not know if there is any association between
these rDNA differences and brewing quality.
Chemistry About 400 cone samples from the 1993 crop were analyzed and 65 storage samples from
the 1993 crop were analyzed. Almost 200 bale samples from the 1994 crop were analyzed and analysis
of over 500 cone samples is pending. Data summaries are available upon request. During a summary
of our ten-years of essential oil data, we discovered eight single component essential oil markers for
seven commercial cultivars. The eight components and the cultivar identified are methyl geranate Centennial, aromadendrene - Chinook, 2-dodecanone - Eroica, 2-undecanol - Nugget, geranyl acetate Cascade, /-selinene - Chinook, methyl dodecenoate - Cluster, methyl 3,6-dodecdienoate - Galena. We
also observed a relationship between the levels of C-4 and C-5 alcohol esters and methyl ketones. For
the central European varieties, Spalter, Tettnanger, Saaz, Hersbrucker, and Hallertauer mf, we found
that the C-4 and C-5 alcohol esters were lower than all other cultivars studied. Cultivars such as Fuggle
and Perle that are described as aroma cultivars had relatively low levels of these esters. The central
European aroma varieties studied had higher levels of methyl ketones in their essential oils than most
other cultivars. Although other hops have low levels of the C-4 and C-5 alcohol esters, low levels of
this group of essential oil components appears very characteristic of central European aroma hops. We
began this work to find essential oil components that were either present or absent in the central
European hops that could assist us in determining the aroma potential of our selections. The
observations reported suggest that measuring the levels of C-4 and C-5 alcohols and methyl ketones
in new selections will help us identify selections with good aroma potential.
Off-Station Trials Table 2 summarizes yield and chemical data from the trials of Washington selection
8254-167 and USDA selections 21664, 21665 and 21666 in Washington. Washington selection 8254167 has Hallertauer, English and German ancestry (21285 x 64037M). Anheuser-Busch is testing this
selection. The USDA selections came from crosses between Tettnanger females and tetraploid males
representing tetraploid Hallertauer mf, Cascade, Brewer's Gold, English and German ancestry.
Anheuser-Busch is testing these selections also.
RESEARCH PLANS FOR 1995:
1.
Breeding and Germplasm Development
a.
Evaluate plants in the seedling nursery for desirable growth habit and brewing quality.
b.
c.
d.
Provide brewing quality and agronomic data on advanced selections.
Make crosses for pest resistance studies and brewing quality traits.
Identify seedlings showing resistance to hop downy mildew.
e.
Continue to rate seedlings selected for aphid resistance.
BENEFIT: Breeding program continuity leading to improved hop materials for grower and brewer
evaluation.
2.
Molecular Genetics
Continue to develop a set of RFLP and RAPD probes useful in marking genes of economic
importance (e.g., aphid resistance).
BENEFIT: Provide additional tools that might improve future selection efficiency of the breeding
program.
3.
KENNY
Chemistry
a.
Use analytical chemistry to judge hop samples from the breeding program.
b.
Investigate analytical methods useful for selection of new varieties.
Pa8e 47
BENEFIT: Allow measurement of brewing quality in selections and provide tools for increased
selection efficiency.
4.
Off-station Trials
Monitor off-station trials.
BENEFIT: Organize and report data useful to growers and brewers.
PROCEDURE:
Obtain new hop germplasm through introduction from foreign sources, indigenous hops, and by
hybridization. Evaluate progeny in the field for good agronomic traits. Evaluate progeny by GC, HPLC
and GC/MS techniques for desirable flavor and aroma characteristics. Use laboratory techniques to
measure the resistance to hop downy mildew of seedlings from crosses made to study the inheritance
resistance to this disease. Measure the resistance to hop aphid in progeny from crosses to study
inheritance of resistance to hop aphid. Develop and evaluate RFLP and RAPD molecular markers for
economically important traits.
TIME FRAME: Ongoing - no specific target for completion of any objective.
KENNY
PaSe 48
t»
>H0
8935-025
8935-024
8935-023
8935-016
8932-088
8935-008
8935-014
8932-082
8917-077
8918-041
8932-005
8914-017
8915-014
8913-005
8910-053
8910-014
8910-049
8910-001
8909-009
8909-031
8696-003
8695-003
8694-002
8553-065
94
94
93
94
94
93
94
94
93
94
93
94
94
93
94
93
94
94
93
94
93
94
93
94
94
93
94
94
94
93
94
93
94
94
94
93
94
93
94
93
94
93
94
93
2143
1677
601
1976
1245
444
2192
1913
318
511
584
1657
1991
1089
2557
569
431
2813
774
1136
1639
2426
1042
1550
1733
1600
1122
1808
1719
89
965
829
2379
1192
2022
1708
1604
1565
1848
875
4115
2652
2498
1592
3.8
2.8
4.4
4.0
4.3
7.9
3.9
7.5
4.6
7.1
6.7
3.1
7.5
4.5
3.0
7.0
4.6
5.6
4.1
6.4
5.6
7.8
6.2
14.6
5.6
13.1
8.7
7.8
7.1
12.1
7.1
10.3
7.9
16.7
6.4
11.8
6.8
9.8
5.7
10.7
7.0
9.2
7.2
11.7
4.7
12.9
5.4
11.0
6.1
13.7
10.9
6.0
5.4
12.6
12.0 . 6.6
6.7
12*6
5.8
3.8
5.5
5.0
5.9
6.7
6.4
5.7
6.9
8.5
6.9
7.3
7.6
7.0
8.0
8.6
6.7
6.3
6.4
6.8
9.3
9.7
9.5
9.0
6.5
5.2
7.2
5.9
4.4
3.0
X
/f-acid
0.265
0.232
0.237
0.244
0.268
0.225
0.250
0.233
0.234
0.217
0.228
0.216
0.222
0.231
0.249
0.234
0.247
0.215
0.299
0.238
0.253
0.250
0.216
0.250
0.230
0.228
0.258
0.225
0.216
0.220
0.226
0.219
0.225
0.246
0.231
0.236
0.213
0.206
0.218
0.258
0.244
0.264
0.249
0.253
HSI
43
49
49
43
45
44
37
36
33
34
34
44
47
50
41
48
40
44
50
40
48
44
47
58
51
56
51
64
43
44
42
46
47
41
44
46
38
43
42
43
39
39
40
44
16
20
18
17
16
16
19
16
14
16
12
20
23
23
24
27
14
19
21
15
20
14
22
29
28
32
25
42
23
22
20
22
22
19
14
14
10
13
14
14
12
11
19
22
Coh Col
X
X
8.2
5.8
8.4
12.2
11.3
11.7
9.8
12.0
10.0
10.3
10.5
13.4
20.8
18.7
16.5
19.2
17.4
24.7
18.2
16.7
16.3
16.2
18.9
17.6
16.5
19.8
16.9
18.1
18.6
19.4
9.6
10.5
12.6
12.2
15.3
14.2
14.6
16.6
13.1
13.2
19.0
18.5
11.7
13.2
X
dff/J
1.1
1.1
0.9
1.8
1.9
1.5
0.5
0.6
0.4
1.2
1.6
1.4
2.4
2.3
0.9
1.7
1.5
2.1
1.8
1.4
1.9
1.3
1.6
2.8
2.0
2.2
0.6
2.3
1.8
1.9
0.7
0.9
1.1
0.9
1.2
1.0
0.9
1.1
0.9
1.1
1.0
1.0
0.8
0.8
0.59
0.60
1.13
1.90
1.90
1.27
1.14
1.01
0.44
0.45
0.57
1.00
2.30
1.68
3.01
1.97
1.51
3.36
1.50
2.39
1.54
2.08
1.06
3.00
1.66
2.25
2.84
2.75
2.26
1.61
0.66
0.37
0.58
0.83
1.96
1.29
0.57
0.98
0.49
0.59
1.22
1.35
1.38
1.14
3.74
3.41
3.35
2.42
2.52
3.52
1.46
1.73
3.43
2.64
22.74
2.91
3.21
3.45
3.42
3.43
2.90
2.57
2.51
2.14
2.93
3.24
1.69
1.53
1.67
1.90
1.99
2.27
2.16
2.10
2.19
1.77
2.19
1.80
1.94
1.50
1.93
2.09
2.14
2.35
3.29
3.45
3.36
3.35
Ratio
X
51.7 24.4
53.4 23.6
58.4 21.3
55.0 17.4
57.2 14.0
56.5 16.2
56.6 17.6
47.6 22.0
32.3 30.7
23.9 37.6
32.2 31.6
52.0 18.7
7.5
53.2
8.7
51.5
62.9 14.9
59.1 17.4
53.3 10.9
63.6
8.1
50.6 13.6
9.8
54.3
46.0 13.0
62.5 16.0
43.5 24.8
51.3 24.1
46.9 23.8
36.1 29.1
57.6 19.0
64.4
8.1
59.7 16.2
45.4 23.8
51.3 11.8
45.7 12.4
37.7 26.3
48.9 23.9
54.1 20.5
45.6 25.6
40.8 17.9
48.7 14.8
40.3 26.0
44.9 20.9
44.0 28.5
38.6 32.7
60.3 15.7
49.4 20.6
X
Fresh Essential Oil Data
Hum
Myr
H/C
ml/
Ratio lOOq
a/p
Plants established from rhizome pieces in 1993.
0.0
0.0
0.1
2.3
1.9
1.4
0.0
0.0
0.2
0.3
0.2
0.0
19.9
17.5
0.1
0.0
15.4
10.6
12.5
17.6
17.8
0.0
0.0
0.0
0.1
0.1
0.0
0.0
0.0
0.0
0.1
0.1
0.1
0.1
0.0
0.0
0.0
0.1
0.2
0.1
0.1
0.2
0.0
0.0
Farn"
X
73.2
57.5
46.4
68.6
38.7
42.7
32.5
47.7
67.6
86.0
67.4
66.3
X
0.420
0.577
0.737
0.489
0.916
0.829
0.967
0.725
0.453
0.333
0.494
0.457
0.44
0.33
0.39
0.15
0.73
0.44
0.47
0.45
0.42
0.30
0.32
0.28
3.92
2.01
3.45
3.61
3.10
3.49
2.61
2.40
2.39
2.61
2.19
3.47
lOQq Ratio
8.8
5.6
3.2
3.2
3.2
2.9
8.3
1.3
5.9
2.9
2.2
5.0
X
After 6 Months RT Storage
o-Rem
HSI
ml/
H/C
H II
Yield and chemical analysis of advanced selections grown at Prosser, Washington in 1993 and 1994.
Yield a -acid
X
Selection Yr (lb/A)
Table 1.
©
era
13
8971-003
8970-039
8970-036
8970-034
8970-018
8970-033
8970-008
8970-012
8970-014
8970-015
8970-003
8970-002
8966-011
8967-008
8966-004
8966-002
8945-017
8935-051
8935-049
8935-048
8935-046
8935-041
8935-037
8935-038
8935-035
8935-031
8935-032
8935-027
94
93
94
94
93
94
93
94
94
93
94
93
94
93
94
93
94
93
94
93
94
93
94
93
94
94
94
93
94
93
94
93
94
94
94
94
93
94
94
93
94
93
94
93
94
93
94
93
1
1333
1193
3015
2158
669
3249
1975
2491
1797
568
2456
1335
1910
793
1832
1337
1961
1345
1859
1629
1642
1168
1170
798
871
1378
568
597
1037
1345
1756
1090
1242
1554
1141
623
1976
1510
1460
1094
1711
703
2837
1672
3714
1471
3308
943
7.5
6.4
7.5
9.5
7.3
8.8
8.0
7.3
8.9
10.2
6.1
6.9
4.6
5.8
8.5
7.7
7.0
7.0
7.7
8.2
6.4
8.3
. 4.7
5.8
6.9
5.6
5.1
4.3
5.7
9.3
7.4
8.2
4.6
4.p.
6.8
8.3
6.8
6.5
6.1
2.2
7.4
6.4
7.0
6.5
6.7
5.0
7.5
6.4
10.8
8.1
6.9
7.9
5.2
5.5
5.4
4.5
7.6
7.9
7.9
6.5
8.8
10.3
8.7
8.8
3.9
5.7
8.5
7.7
9.0
5.3
8.1
6.4
6.4
7.6
8.6
8.9
2.5
5.1
4.7
5.0
8.2
7.6
3.0
8.8
8.6
10.0
3.7
6.0
4.4
6.4
5.0
4.3
5.1
9.7
5.6
5.7
field a -acid /J -acid
X
X
Selection Yr (lb/A)
Table 1. Continued
0.233
0.256
0.226
0.223
0.251
0.225
0.230
0.220
0.231
0.231
0.229
0.240
0.226
0.252
0.234
0.248
0.229
0.224
0.242
0.244
0.216
0.226
0.244
0.244
0.240
0.210
0.233
0.250
0.231
0.242
0.227
0.244
0.266
0.227
0.225
0.245
0.228
0.212
0.228
0.226
0.210
0.214
0.242
0.299
0.222
0.208
0.220
0.209
HSI
20
20
16
18
16
18
20
14
15
14
16
15
19
15
17
15
14
15
21
19
26
25
17
14
16
18
14
10
21
20
14
14
21
16
12
23
15
11
20
20
19
14
15
113
12
11
20
19
32
29
40
42
44
46
40
47
40
40
38
36
38
42
39
46
42
41
31
29
53
52
44
37
37
36
43
40
42
41
41
40
38
44
44
46
45
40
41
39
38
35
35
44
45
36
45
43
:oh Col
X
X
13.9
18.9
14.8
10.7
10.0
15.5
14.5
19.1
17.5
8.4
11.8
11.3
12.1
10.1
8.6
10.8
18.9
13.1
14.0
8.6
15.1
13.3
8.3
13.8
13.5
11.7
17.8
14.7
15.8
7.1
10.9
13.2
12.7
15.3
14.6
10.7
17.0
15.0
18.3
11.4
12.0
16.0
17.2
16.3
14.0
16.1
13.7
15.3
X
ttt-fi
0.5
0.9
1.1
0.8
1.2
0.6
1.0
0.9
0.7
0.7
1.4
1.3
0.5
0.9
0.6
0.7
1.2
1.1
0.4
1.1
1.3
1.2
0.8
1.0
0.6
1.1
1.0
1.0
0.9
1.0
0.8
0.7
0.9
1.2
1.0
0.4
0.9
0.9
0.7
0.8
0.8
1.1
1.0
0.8
1.0
0.8
1.2
1.0
1.18
1.28
1.19
1.28
1.79
2.00
1.97
0.64
0.96
2.09
1.47
2.32
1.50
0.74
1.05
1.12
1.23
0.75
1.04
1.46
1.60
0.81
0.99
1.08
0.48
0.99
0.72
1.02
1.15
1.97
1.39
0.56
0.75
0.76
1.56
1.66
1.23
1.03
1.15
0.82
0.95
0.88
1.20
1.94
0.91
1.89
1.56
1.20
3.47
6.64
3.49
3.52
3.42
1.79
1.76
3.50
3.43
3.46
3.31
3.54
3.20
3.51
3.42
3.49
3.50
3.59
1.71
1.68
3.41
3.39
3.19
3.63
3.22
3.25
3.38
3.52
3.33
3.46
3.43
3.60
3.43
1.84
3.44
3.40
3.50
3.43
3.37
3.44
3.50
3.53
3.38
3.55
3.41
3.56
2.82
2.76
H/C
Ratio
23.6
25.0
27.5
21.3
31.4
11.5
20.4
22.5
18.8
226.4
29.9
30.3
24.8
26.6
24.9
33.5
27.9
26.5
17.5
15.8
43.1
44.9
16.8
15.7
15.3
11.9
37.4
33.1
33.8
26.9
26.1
23.7
39.3
26.7
36.2
32.5
34.0
34.1
29.7
27.5
30.5
32.0
32.6
34.9
25.5
29.1
26.3
27.6
51.8
44.0
44.7
55.8
34.1
66.2
45.2
52.2
59.4
47.2
41.9
41.1
47.1
37.2
49.0
35.6
45.2
46.9
43.2
49.2
23.5
21.7
31.4
40.9
37.2
44.7
33.0
38.7
39.1
47.9
47.9
50.8
26.6
34.6
34.0
38.4
35.4
36.1
44.2
47.1
40.2
38.7
38.8
31.2
49.5
43.8
45.2
41.4
X
Hum
X
Myr
Fresh Essential Oil Data
ml/
Ratio lOOq
a/p
0.0
0.3
0.1
0.3
0.7
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.1
0.0
0.0
0.1
0.0
0.0
0.0
0.3
0.1
0.0
0.6
0.0
0.1
0.0
0.1
0.1
0.1
0.1
0.1
0.1
0.0
0.1
0.1
0.1
0.0
0.2
0.0
0.4
0.2
0.0
0.0
0.1
0.0
Farn
*
76.0
55.5
30.2
68.8
87.1
60.3
69.5
63.1
44.0
X
cTRem
0.348
0.634
1.133
0.369
0.286
0.569
0.456
0.540
0.799
HSI
H/C
0.48
0.47
0.37
0.26
0.88
0.34
0.39
0.43
0.49
4.04
3.86
3.84
3.86
3.84
2.12
3.99
4.09
1.93
lOQg Ratio
ml/
After 6 Months RT Storage
6.6
3.2
9.6
5.5
5.9
5.4
9.4
4.9
5.3
X
H II
D
09
3.51
3.48
2.25
2.36
2.43
3.38
2.69
2.50
3.29
3.48
1.91
3.06
1.25
1.70
3.38
3.57
2.92
3.21
2.20
1.98
2.82
3.00
2.31
3.32
3.50
50.2
51.4
41.5
50.6
49.1
39.1
43.5
21.9
28.2
67.3
39.2
43.7
51.5
36.1
28.8
47.2
51.4
51.1
31.4
31.7
44.1
44.8
55.6
31.1
54.3
11.5
21.6
11.7
14.9
23.1
41.6
36.3
9.8
21.3
28.0
23.3
31.9
36.2
22.0
21.4
19.2
35.2
35.8
28.2
28.1
20.1
29.2
11.3
15.4
26.8
Elsasser x 8657-017M
8971
8984
8254-146 x 8685-063M
8932
8910 Apolon x 8685-014M
8983
8254-146 x 8685-014M
8982
8970
8254-146 x 8658-039M
Comet x 21110M
8967
8696
Brew Gold x 8658-039M
21373 x 21337M
8695
8918
8913
8914
21163 x OP
8553
8694 21373 x 21088M
8917
3.58
2.99
21373 x 8153-032M
0.34
0.73
8909 Apolon x 8659-023M
0.770
1.100
8980
48.2
30.8
8254-146 x 8657-017M
0.0
0.0
0.0
0.0
0.1
0.1
1.0
0.1
0.1
0.0
0.0
0.1
0.1
1.5
0.1
0.0
0.0
0.0
0.0
0.1
0.1
0.0
0.0
0.0
0.1
8966
Selection Pedigrees
3.16
2.27
1.47
1.87
2.99
2.15
1.05
1.08
0.81
0.87
1.21
1.33
1.25
1.02
1.17
1.38
1.63
1.27
1.06
2.47
2.57
0.81
1.01
1.27
1.71
Brewer's Gold x 60028M
0.7
0.6
0.4
0.5
0.6
0.7
1.9
0.9
0.8
0.9
0.8
1.1
1.1
1.0
0.9
0.7
0.7
0.9
0.9
0.8
0.8
0.9
0.9
0.7
1.1
8915
19.2
16.7
15.7
16.6
16.8
14.2
13.3
13.1
12.8
17.8
16.9
13.6
14.1
9.4
17.4
10.9
17.7
16.9
17.6
18.0
17.1
8.2
11.9
12.2
17.2
8976
44
42
54
40
47
45
47
48
48
52
46
48
39
48
36
35
42
40
47
48
39
43
50
50
40
8972
23
23
21
21
25
23
20
16
15
14
11
20
17
26
16
16
13
15
15
23
21
22
21
16
16
8254 181 x 8685-063M
8254 181 x 8685-014M
8254 181 x 8659-045M
8254 181 x 8658-039M
8254 167 x 8659-045M
8254 146 x 8693-043M
2.7
8.4
After 6 Months RT Storage
a-Rem
HSI
ml/
H/C
H II
lOOg Ratio
X
X
L1 Cluster x 21237M
0.223
0.247
0.234
0.208
0.224
0.266
0.245
0.222
0.236
0.209
0.255
0.235
0.254
0.226
0.212
0.228
0.220
0.212
0.206
0.236
0.247
0.248
0.260
0.233
0.219
Fresh Essential Oil Data
Farn
Hum
ml/
H/C
Myr
X
Ratio lOOg Ratio
X
X
or/A
Elsasser x 8685-014M
11.3
10.7
11.3
11.0
10.3
8.4
4.6
6.9
7.1
9.3
9.3
6.4
6.6
4.6
9.1
6.2
10.7
8.9
9.4
10.0
9.5
4.2
6.2
7.2
8.3
X
or+/f
8945
7.9
6.0
4.4
5.6
6.5
5.8
8.7
6.1
5.8
8.5
7.6
7.1
7.5
4.8
8.3
4.7
7.1
8.0
8.3
8.0
7.5
3.9
5.7
5.1
9.0
Coh Col
X
X
8935
3284
552
1327
851
2524
1460
355
1766
836
1725
1031
1483
493
1476
916
711
884
2461
1737
1896
1576
2106
1777
737
1028
X
HSI
Brewer's Gold x 21237M
94
93
94
93
94
93
94
94
93
94
93
94
93
94
94
94
93
94
94
94
93
94
93
94
94
X
-acid fi -acid
Brewer's Gold x 21235M
8984-002
8984-007
8983-028
8983-003
8983-016
8983-025
8980-044
8982-041
8983-001
8980-043
8980-038
8972-016
8976-018
8971-023
8971-017
8971-008
Selection Yr (lb/A)
Yield a
Table 1. Continued
re
(re
£>
13
rfl
94
94
Grandview
Sunnyside
21665
21666
1.60
20
20
15
15
Coh
%
0.65
1.76
0.87
0.33
1.07
0.58
ml oil/
100g
0.89
0.69
a/0
Ratio
17.3
22.0
24.4
15.9
27.2
37.5
46.0
51.8
Hum
%
0.3
0.3
Farn
%
24.4
9.9
Myr
%
Remain
3.36
3.46
3.58
3.32
% a-acid
H/C
Ratio
HSI
100g
ml oil/
H/C
Ratio
2 USDA 21665was establishedfrom softwood cuttings in 1994and was not harvested. (USDA 21664and 21665were established from softwood cuttings in 1993.)
0.299
0.223
8.10
4.88
0.234
0.261
0.237
HSI
6.40
7.3
3.88
£-acid
%
1The very poor yield is possibly due to moisture stress.
754
NA2
7.07
927
94
Moxee
21664
5.67
1,622
92
6.0
2.67
2651
1,344
a-acid
%
94
Yield
(lb/A)
93
Moxee
8254-167
Yr
Location
Selection
%
HMEB
After Six Months Room Temperature
Storage
Table 2. Yield and chemical analysis data for experimental hops grown in Washington commercial trials.