The University of Maryland Extension Agriculture and Natural Resources Profitability Impact Team
proudly presents this bi-weekly publication for the commercial vegetable and fruit industry.
Field Observations from
Southern Maryland
By Ben Beale
Extension Educator & CED,
Agriculture
St. Mary’s County, UME
bbeale@umd.edu
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Hot and dry conditions continue to take the
headlines in Southern Maryland. Excessive heat has
caused problems with pollination and fruit set.
Irrigation systems are running overtime to keep up
with the water demand. Growers using alternative
water sources should be careful to check salinity
levels and particulate matter. Sand filter s tend to
clog much faster when ponds and surface water
levels drop.
Main season crops such as tomato, pepper, melon,
sweet corn and squash are all being harvested.
Spider mites are showing up, especially in
watermelon and cucumber fields. Stink bug damage
can be found on many tomatoes. Japanese beetle
populations remain high.
Powdery mildew is now evident on most farms
growing cucurbit crops
Summer Field Observations from
WyeREC
By Michael Newell
Horticultural Crop Program Manager, UME
mnewell@umd.edu
Peaches
Despite the fact that peach bloom was about three
weeks earlier than in 2011, harvest is running only about
one week earlier than in 2011. Continued dry weather in
our area means the irrigation well is working over-time
this season. Thus far, Brown rot has been absent in our
orchards.
Volume 3 Issue 7 July 12, 2012
Apple/Pear
FireBlight damaged shoots can still be found in the
orchards. Even apple varieties that are listed as
FireBlight resistant had a few strikes this season. The
dry weather has allowed me to extend time between
sprays for the summer disease complexes. However,
when the rain comes (and I know it will) strawberrstrabe
ready to apply materials for Fly Speck, Sooty Mold and
the summer rots.
Strawberry Plasticulture
If you have not ordered plants for
Fall planting, do not wait! The link
below of strawberry material suppliers is
courtesy of the North Carolina
Strawberry Association at:
http://www.ncstrawberry.org/docs/2012PlantSupplierList.pdf
An alternative to buying ready to plant plugs is to make
your own from runner tips. The following article by
Kathy Demchak and Steve Bogash is from the Penn
State small fruit and vegetable gazette, volume 16,
Issue 7.
1) Use tips only from a reputable source. Tissue
cultured mother plants are the preferred source. Using
tips from your own or other local fields can create future
problems, as there is the potential to move diseases and
mites from field to field. Also, many varieties are
patented and require licensing in order to take cuttings.
USDA varieties are not patented, and can be propagated
at no charge.
2) Ideally, tips should be planted as soon as they arrive.
However, if this is not possible, the tips may be stored
at 34˚F and 75-80% humidity for up to 2 weeks from
the date they were harvested from the mother plants. If
you're in a pinch for time and cooler space, pack the
plants in ice. Allow 35 days from planting to grow a
field-ready plug. Trim any runner cord to a 3/8-1/2 inch
stub before planting.
3) Carefully cull the tips you are going to plant.
Anything that looks at all questionable should be
discarded.
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4) Sort tips by size. Do not plant small and large tips in
the same trays, as the smaller plants are likely to get
shaded. The smaller plants in this now lower canopy in
the flat are ripe for botrytis and powdery mildew as air
circulation will be poorer in the lower canopy.
put down a layer of groundcover fabric before rooting
plants outdoors. Make sure your misting set-up is
working ahead of time.
2) Shade cloth can be used to limit plant desiccation,
but is not recommended. This will slow the time from
sticking the tips to having field-ready plugs by about a
week.
5) Plant the tips in plug trays with 50-cells/tray. Use a
sterile media designed for rooting herbaceous “barerooted” plants. This includes most professional grower
mixes. If you are recycling trays, be sure to remove all
organic matter from them, then chlorine dip (1 part
liquid bleach to 9 parts clean water) the trays prior to
use. Be careful to avoid contamination of the
propagation area.
3) Soil inoculants such as Plant Shield and Mycostop
may be advantageous in preventing soil-borne diseases.
However, no definitive research has been done using
these products on strawberry tips at this time. In other
crops, these products have prevented a wide range of
soil-borne diseases.
6) The hook on the tip should be just in the potting
media. Do not bury the crown.
4) Due to the constant misting, control of diseases
should be managed primarily with good ventilation. Any
fungicides that are applied during the time the tips are
being misted will be washed off too quickly to
accomplish anything. However, a fungicide application to
the plants prior to planting is probably a good idea.
7) Do not fertilize just planted tips. The fertilizer charge
in most potting media will be sufficient until the plants
are well-rooted. Fertilize for the first time at two weeks
after planting using 100 ppm of nitrogen with calcium
nitrate as the source, and repeat at weekly intervals. If
you are holding the plants for longer than 4-5 weeks
(thus creating super plants), switch to 20-20-20 at 100
ppm of nitrogen for later applications.
5) Scout the plants for spider mites. Their eggs are tiny
so use a hand lens. If any eggs or mites are found, treat
before planting in the field. Materials for two-spotted
spider mite control include: Vendex, Acramite, Oberon,
Kanemite, Portal and Zeal. Zeal is only for eggs and
immatures. As always, growers should closely follow
label restrictions and requirements.
8) Your goal is to keep the leaves moist until the tips
start to create their own roots. Hot, sunny days will
require extra mist, while cooler, cloudy days less mist.
The assumption with the following misting regimen is
that you will be placing the new tips in a greenhouse or
high tunnel. Enclosed structures will require less misting
as wind will not dry the leaves as with plants growing
outdoors. Do not allow the surface of the leaves to dry
for the first 7 days. Mist using fogger nozzles of an
intermediate discharge rate. Start with the following
misting regimen, but adjust it as needed to prevent
over-watering or desiccation of the leaves:
a) Time for the system to reach operating pressure
needs to be factored in as this regimen assumes
actual misting time.
b) Day 1-7: Use 5 seconds of mist every 15 minutes.
c) Day 7-12: Gradually reduce misting. Keep the
media moist. Misting should be terminated by the end
of this period.
d) After week 3, the plants should be well-rooted and
ready to begin conditioning for field planting. Keep the
media moist, but expose the plants to full sun by
setting them on a field wagon or on groundcover
fabric. Keeping them in a greenhouse or high tunnel is
OK, but do not mist and maintain good airflow.
e) Do not mist after sundown, even at first. Some
growers believe misting after sundown can create
bigger plugs, but the greater chance of disease offsets
any possible benefits.
Vegetable Crop Insect
Update
By Joanne Whalen
Extension IPM Specialist
jwhalen@udel.edu
Lima Beans
Be sure to scout fields for leafhoppers, spider mites as
well as plant bugs and stink bugs. As soon as pin pods
are present, be sure to watch carefully for plant bug and
stinkbug adults and nymphs. As a general guideline,
treatment should be considered if you find 15 adults
and/or nymphs per 50 sweeps. The higher rates of
labeled products will be needed if stinkbugs are the
predominant insect present.
Melons
Continue to scout all melons for aphids, cucumber
beetles, and spider mites. The first beet armyworm
(BAW) larvae have been detected in melon fields. As a
reminder, both cucumber beetles and beet armyworm
feed on rinds. Since BAW are difficult to control, be sure
to select a material that is labeled for beet armyworm
(BAW) on melons such as Coragen, Avaunt, Intrepid,
Radiant, Synapse/Belt or Vetica. The pyrethroids will not
provide effective BAW control.
Additional Strawberry Plant Care
1) Plants can be rooted in either an enclosed structure
(greenhouse/high tunnel) or outdoors. If outdoors,
choose a protected location to keep the unrooted tips
from being dislodged by wind or heavy rain. Be sure to
2
Pumpkin Spray Program 2012
Peppers
As soon as the first flowers can be found, be sure to
consider a corn borer treatment. Depending on local
corn borer trap catches, sprays should be applied on a 7
to 10-day schedule once pepper fruit is ¼ – ½ inch in
diameter. Be sure to check local moth catches in your
area by calling the Crop Pest Hotline (instate: 800-3457544; out of state: 302-831-8851) or visiting our
website at: http://ag.udel.edu/extension/IPM/traps/latestblt.html
You will also need to consider a treatment for pepper
maggot. Beet armyworm larvae can be found in fields
and can quickly defoliate plants. Be sure to use a
material that provides beet armyworm control — The
pyrethroids will not effectively control this insect.
By Kate Everts, Vegetable
Pathologist,
University of Delaware and
University of Maryland;
keverts@umd.edu
I frequently am asked for a “good” spray program for
pumpkins. This is always difficult because a spray
program depends on field history (i.e. has Phytophthora
crown rot occurred in the field), production practices
(no-till vs. bare ground), and the grower’s philosophy
about control (Cadillac treatment program vs. minimal
inputs).
Preventative practices are more effective than trying
to minimize the damage from a disease after it occurs.
Practices such as growing pumpkin on a no-till cover
crop and using a powdery mildew tolerant cultivar will
allow growers to stretch their spray interval.
Powdery mildew is the most common disease – it will
damage leaves and the pumpkin “handles”. Downy
mildew is an extremely damaging disease, however it
does not overwinter here and sprays for downy mildew
should only be applied when it is present in the MidAtlantic. Other diseases that occur, such as Bacterial wilt
or virus diseases need to be treated by managing the
vectors.
Potatoes
Continue to scout fields for Colorado potato beetle
(CPB), aphids and leafhoppers. Controls will be needed
for green peach aphids if you find 2 aphids per leaf
during bloom and 4 aphids per leaf post bloom. This
threshold increases to 10 per leaf at 2 weeks from vine
death/kill. If melon aphids are found, the threshold
should be reduced by half.
Snap Beans
Continue to scout for leafhopper and thrips activity in
seedling stage beans. We are seeing a significant
increase in leafhopper activity in seedling stage beans.
Sprays will be needed for corn borer at the bud and pin
stages on processing beans. As earworm trap catches
increase, an earworm spray will also be needed at the
pin stage. Additional sprays may be needed after the pin
spray on processing beans. Since trap catches can
change quickly, be sure to check our website for the
most recent trap catches and information on how to use
this information to make a treatment decision in
processing snap beans after bloom at:
http://ag.udel.edu/extension/IPM/traps/latestblt.html and
Keep the following in mind:
● Know what diseases are the most common on your
farm. Previous problems with black rot, Phytophthora
blight, anthracnose, scab or other diseases may indicate
that these diseases are likely to be problems again.
● Begin spraying when vines begin to run.
● Use a protectant such as chlorothalonil every time
(don’t worry about resistance developing).
● Spray every 7 to 14 days.
http://ag.udel.edu/extension/IPM/thresh/snapbeanecbthresh.html
Once pins are present on fresh market snap beans and
corn borer trap catches are above 2 per night, a 7-10
day schedule should be maintained for corn borer
control.
● The most common disease in our area is powdery
mildew. However it is not always present early in the
season. Scout 50 old leaves in your field for powdery
mildew lesions. If powdery mildew is present in the field,
apply materials that are targeted for it. If it is not
present, spray with a protectant, then scout again
before your next spray and adjust the spray accordingly.
Sweet Corn
Continue to sample all fields from the whorl through pretassel stage for corn borers, corn earworms and fall
armyworm. We have started to see an increase in fall
armyworm damage in whorl stage corn. A treatment
should be considered when 12-15% of the plants are
infested. Since fall armyworm feeds deep in the whorls,
sprays should be directed into the whorls and multiple
applications are often needed to achieve control. The
first silk sprays will be needed for earworm as soon as
ear shanks are visible. Be sure to check both blacklight
and pheromone trap catches for silk spray schedules
since the spray schedules can quickly change at:
http://ag.udel.edu/extension/IPM/traps/latestblt.html and
● Familiarize yourself with the extension publication
“Commercial Vegetable Production Recommendations”
section on pumpkins. Fungicides included in the
“Recommendations” have been tested and performed
well in the Mid-Atlantic region.
● A good fungicide spray program will increase yields
and improve quality. The single best way to improve
handle quality is to control foliar and fruit diseases with
fungicides.
http://ag.udel.edu/extension/IPM/thresh/silkspraythresh.html
You can also call the Crop Pest Hotline (in state: 800345-7544; out of state: 302-831-8851).
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The program:
The best way to save money on your spray program is
to start with a protectant program such as either
chlorothalonil plus copper or mancozeb plus copper. Add
targeted products to your protectant program based on
what diseases are in the area or known to be on the
farm (downy mildew, powdery mildew, Phytophthora
crown and fruit rot, etc.)
Tomato Pollination and
Excessive Heat
By Jerry Brust, IPM Vegetable Specialist
University of Maryland
jbrust@umd.edu
Powdery Mildew: The following are targeted for
powdery mildew and have been tested in our region.
Apply them with a protectant. Select two that are in a
different FRAC code groups, and alternate them.
Product (FRAC Code)
Quintec (13)
Micronized Wettable
Sulfur (M2)
Procure (3)
Rally (3)
Tebuconazole:Folicur,
etc. (3)
Inspire Super (3 + 9)
Pristine (11 + 7)
The extreme heat we had will play havoc
on tomato fruit that was just flowering or ripening
causing problems in fruit development due to poor
pollination. Constant exposure of a tomato plant to high
temperatures (day/night temperatures of 95/80 °F)
significantly reduces the number of pollen grains
produced and released per flower and decreases the
pollen’s viability. Most pollen is shed between 10:00 a.m.
and 4:00 p.m. and 3-hours or more at 103oF on two
consecutive days can cause fruit set failure.
Efficacy on Powdery
Mildew
excellent
very good (may cause
injury at high temperatures
– see label)
good
good
good
Temperatures at night may play a more important role
in determining whether or not pollination takes place
than day time temperatures. This is because ideal fruit
set occurs within a very narrow range of night
temperatures (60°-70° F). If tomato plants experience
night temperatures above 75°F, interference with the
growth of pollen tubes can occur preventing normal
fertilization and causing blossom drop (fig 1). Prolonged
high humidity (>80%) also will hinder good fruit set as
the pollen either will not shed freely or the pollen grains
may bind together, resulting in poor pollination. Poor
pollination may result in under-size fruit that looks
‘normal’ but is just a great deal smaller.
good
good
Downy Mildew: Management of downy mildew should
use the following products tested in our area. Select two
that are in different FRAC code groups, and alternate
them.
Product (FRAC
Code)
Presidio (43)
Ranman (21)
Previcur Flex (28)
Tanos (11 + 27)
Curzate (27)
Gavel (22 + M3)
Efficacy on Downy Mildew
Other problems include poor development of the gel
inside the fruit. This causes the fruit to appear angular
and soft when squeezed (fig 2). When this type of fruit
is cut in half, open cavities can be seen between the
seed gel and the outer wall (fig 2). High temperatures
during the ripening period additionally can cause
‘internal whitening’ in tomato fruit (fig 2). This white
tissue only is noticeable when the fruit is cut. The hard,
white areas tend to be in the vascular tissues in the
outer and center walls of the fruit. Low potassium levels
are also associated with ‘internal whitening’. There is not
a great deal that can be done about any of the
environmental problems other than to be sure to water
enough and do not over fertilize during these extreme
conditions. Although growth regulating chemicals can be
used sometimes to help fruit set under cooler than ideal
conditions there is no growth regulator that will induce
normal fruit development under high temperature
conditions.
excellent
excellent
good (the pathogen may be
developing resistance)
good in alternation or tank mix
good in alternation or tank mix
good in alternation or tank mix
Plectosporium can be managed with applications of
Quadris Top, Cabrio or Flint.
Phytophthora crown and fruit rot needs to be
managed intensively. In fields with potential problems,
apply Mefenoxam (Ridomil Gold or Ultra Flourish) preplant for early season control. Once the canopy closes,
subsoil between the rows to allow for faster drainage
following rainfall. Fungicide applications will only
suppress Phytophthora, and reduce spread.
When conditions favor Phytophthora crown and fruit rot
development, tank mix one of the following fungicides
with fixed copper: Revus (FRAC code 40), Ranman
(FRAC code 21), Presidio (FRAC code 43), Forum (FRAC
code 40), or Tanos (FRAC code 11 + 27).
4
Fruit Loads in Vine Crops
By Gordon Johnson
Extension Vegetable & Fruit Specialist
University of Delaware
gcjohn@udel.edu
Early watermelons are sizing now,
later plantings are setting fruit, pickle
harvest is underway, and pumpkin
planting is finishing up. A common
question from growers and crop
consultants is how many fruit should a
plant carry and what will affect fruit set
and fruit “carry” in vine crops.
For watermelons, a healthy, vigorous
plant may set 3-7 fruits initially. However,
for mid-size and larger watermelons, the
plant will only carry 2-4 fruit at any time. Smaller fruited
varieties will more fruits per plant but essentially the
same amount of pounds as larger types. This is the
carrying capacity of the plant and is directly related to
the quantity of photosynthates being produced by the
plant, mostly in the leaves. Any additional fruits, even if
initially set, will be aborted. Once the first fruit ripens
and is harvested, additional sets can be carried. To carry
the maximum amount of fruit, it is necessary to maintain
high plant vigor and good foliage health. This requires
paying close attention to irrigation and fertility
programs; having excellent disease, insect, and mite
control; and having good pollinator activity during
pollination and fruit set. If average fruit carry is less
than 2 per plant in watermelons, that is a sign that the
plants have reduced vigor and are under stress.
Repeated fruit set depends on maintaining vine health
through the season.
Fig. 1 Blossom drop (arrows) in tomato due to high night
temperatures
Another factor to consider is where fruit set is
occurring. Crown sets are desired in watemelons,
especially in early plantings. Crown sets are those that
occur on nodes closest to the base of the plant, within
the first 8 nodes. Having good crown sets requires that
plants have good early growth so that adequate leaf
area is produced that can support early set fruit as well
as proper pollination (sufficient bees). Lack of crown set
is a sign of poor early growth, early plant stress, or of
problems with pollination.
With pumpkins the carrying capacity is similar;
however, because pumpkins are not repeat harvested as
are watermelons, harvest is limited to those fruits set
initially. Medium sized Jack-o-lantern types will carry 1-2
fruits, larger types closer to 1. All others will be aborted.
Smaller types will carry more depending upon their size
in pounds (for example a variety with 5 lb. average will
carry 4-7 fruits). Maximum carrying capacity in pumpkins
is largely affected by variety (varieties with some heat
Fig. 2 Angular sides of fruit due to poor pollination when cut
open you can see the lack of gel resulting in pockets inside the
fruit as well as ‘internal whitening’--spots in the outer wall.
5
beetles in small fruit. In my observations so far this
season these three pests have been much more of a
problem than BMSB, so don’t forget to figure out what is
causing problems before taking action.
tolerance will carry more fruits in our climate) and
foliage health. Excess nitrogen fertilization will often
delay fruit set in pumpkins.
In gynoecious cucumbers grown for once over pickle
harvesting, there will be two fruits set on adjacent nodes
that are ready for harvest at any one time. These will be
set on nodes 2-6 commonly. The pollinizers that make
up a small percentage of the population will set pickles
every fifth node generally and therefore only one fruit
will be ready for harvest. Yield reductions in gynoecious
pickling cucumbers occur when there is a loss of set so
that fruits are not on adjacent nodes. Parthenocarpic
pickle varieties that set fruit without pollination will
commonly have 4-6 pickles on 3-5 adjacent nodes ready
for harvest at any one time. This allows them to be
planted at much lower densities.
We still have a long season ahead of us and the
situation is certainly dynamic and we cannot let our
guard down but, remember that there have been a lot of
pests that have damaged fruit for a long time and we
certainly need to reduce damage but we have to be
careful not to throw away years of IPM and Beneficial
insects by throwing the kitchen sink at these new pests
when we find the first one. In an effort to help growers
understand and manage SWD below are links to our
completed series of factsheet on SWD. I have had the
pleasure to cooperate with Kathy Demchak, Penn State
Small Fruit Specialist and Dr. David Biddinger, Penn
State Biocontrol Specialist on this series and monitoring
project and would like to thank them for the opportunity
to partner on this project.
BMSB and SWD Update
for Central & Western
Maryland
http://pubs.cas.psu.edu/FreePubs/PDFs/xj0045.pdf
Spotted Wing Drosophila, Part 1: Overview and Identification:
By Bryan Butler
Senior Agent, Carroll County & MidMaryland Tree Fruit Agent, UME
http://pubs.cas.psu.edu/FreePubs/PDFs/xj0046.pdf
Spotted Wing Drosophila, Part 2: Natural History:
http://pubs.cas.psu.edu/FreePubs/PDFs/xj0047.pdf
Spotted Wing Drosophila, Part 3: Monitoring:
I am pleased to report that in general we are holding
our own with these new invasive pests. Traps counts for
both insects have been up and down and the
relationship between trap counts and fruit damage is
certainly a work in progress. At this time the best way
to stay ahead of these pests appears to me to be good
old boots on the ground observation. Keeping a close
eye out in known hot spots and then looking a little
closer when in doubt can give you the edge in
controlling the damage from these pests.
http://pubs.cas.psu.edu/FreePubs/PDFs/xj0048.pdf
Spotted Wing Drosophila, Part 4: Management:
Commercial 2012
Vegetable Production
Recommendations
Maryland EB 236
As I have mentioned previously most hot spots where
SWD problems cropped up were left unprotected for
extended periods of time. Until we get a good handle on
both SWD and BMSB we will have to balance the old
model of cover sprays with IPM. Timely harvest is also
going to play a critical role in fruit damage management.
In a recent SWD flare up on tart cherries that were quite
mature in central Maryland I harvested 50 fruit that
appeared to be damaged by Drosophilidae larva. The
larva were reared out from the fruit in a chamber with
sterile sand in the bottom, there was only 1 male SWD
and 254 non-SWD adults. Thus if fruit is left to over
ripen and not treated you might not have SWD as a
significant problem but there are certainly other
opportunist that can cause damage. I have also noted
this with Brown Stink bugs, Japanese Beetles and sap
On-Line at:
http://www.mdvegetables.umd.edu/files/Mar
yland%20complete%20book%202012.pdf
Also available in a new very interactive
format at the Delaware Extension site at:
http://ag.udel.edu/extension/vegprogram/pu
blications.htm#vegrecs
6
exposed, especially those that are not shaded in the
afternoon. Anything that reduces canopy cover will
increase sunburn, such as foliar diseases, wilting due to
inadequate irrigation, and excessive or late pruning.
Physiological leaf roll, common in some solanaceous
crops such as tomato, can also increase sunburn.
Sunburn in Fruits and
Fruiting Vegetables
By Gordon Johnson
Extension Vegetable & Fruit Specialist
University of Delaware
gcjohn@udel.edu
High temperatures, clear skies and high
light radiation, and long daylengths are a recipe for
developing sunburn in fruits and fruiting vegetables. We
commonly see sunburn in watermelons, tomatoes,
peppers, eggplants, cucumbers, apples, strawberries,
and brambles (raspberries and blackberries).
In crops with large percentages of exposed fruits at
risk of sunburn, fruits can be protected by artificial
shading using shade cloth (10-30% shade). However,
this is not practical for large acreages. For sunburn
protection at a field scale, use of film spray-on materials
can reduce or eliminate sunburn. Many of these
materials are Kaolin clay based and leave a white
particle film on the fruit (such as Surround, Screen Duo,
and many others). There are also film products that
protect fruits from sunburn but do not leave a white
residue, such as Raynox. Apply these materials at the
manufacturer’s rates for sunburn protection. They may
have to be reapplied after heavy rains or multiple
overhead irrigation events.
There are three types of sunburn which may have
effects on the fruit. The first, sunburn necrosis, is where
skin, peel, or fruit tissue dies on the sun exposed side of
the fruit. Cell membrane integrity is lost in this type of
sunburn and cells start leaking their contents. The
critical fruit tissue temperature for sunburn necrosis
varies with type of fruit. For cucumbers research has
shown that the fruit skin temperature threshold for
sunburn necrosis is 100 to 104°F; for peppers, the
threshold is 105 to 108°F, and for apples the critical fruit
skin temperature is 125-127 °F. Fruits with sunburn
necrosis are not marketable.
Fertigation of Vegetable Crops
By Bill Lamont
Extension Vegetable Specialist
Penn State University
wlamont@psu.edu
The second type of sunburn injury is sunburn
browning. This sunburn does not cause tissue death but
does cause loss of pigmentation resulting in a yellow,
bronze, or brown spot on the sun exposed side of the
fruit. Cells remain alive, cell membranes retain their
integrity, cells do not leak, but pigments such as
chlorophyll, carotenes, and xanthophylls are denatured
or destroyed. This type of sunburn browning occurs at a
temperature about 5°F lower than sunburn necrosis
(115 to 120° F in apples). Light is required for sunburn
browning. Fruits may be marketable but will be a lower
grade.
Total fertility requirements in
plasticulture are not different than those
in conventional open-soil culture. With
a drip irrigation system, however,
application can be much more
precise and timed with crop development. Soluble
fertilizers can be added to the drip irrigation water to
provide uniform crop fertilization. A simple “hozon brass
siphon mixer” venturi injector draws soluble fertilizer
from a bucket or jug into the line at a preset ratio
(usually 1:16 or 1 gallon for every 16 gallons of water
flowing through the line). However the hozon injection
system; is suitable only for ⅓ to ½ acre plantings or
less. Other venturi units are available in sizes up to 2
inches in diameter. More expensive injectors with
greater capacity and accuracy use an electric or
hydraulic “pump” to inject fertilizer solutions from a
stock tank into the line. A hydraulic device, called a
Dosatron, placed in the mainline can be set a various
dilution rates and operates with water flowing directly
through it. Use only high quality, soluble fertilizers that
completely dissolve. All fertilizer injections should be
made ahead of either the main filters on the line or the
secondary filters if placed closer to the field, so that any
contaminants are filtered out.
The third type of sunburn is photooxidative sunburn.
This is where shaded fruit are suddenly exposed to
sunlight as might occur with late pruning, after storms
where leaf cover is suddenly lost, or when vines are
turned in drive rows. In this type of sunburn, the fruits
will become photobleached by the excess light because
the fruit is not acclimatized to high light levels, and fruit
tissue will die. This bleaching will occur at much lower
fruit temperatures than the other types of sunburn.
Genetics also play a role in sunburn and some
varieties are more susceptible to sunburn. Varieties with
darker colored fruit, those with more open canopies, and
those with more open fruit clusters have higher risk of
sunburn. Some varieties have other genetic properties
that predispose them to sunburn, for example, some
blackberries are more susceptible to fruit damage from
UV light.
Fertigation is used most commonly to supply nitrogen
and potassium, because they are highly soluble and
move easily through soils to roots. Phosphate and
micronutrients are best applied prior to planting and not
injected through the irrigation system. Other
chemigation applications may include pest control
Control of sunburn in fruits starts with developing
good leaf cover in the canopy to shade the fruit. Fruits
most susceptible to sunburn will be those that are most
7
measures, but check label restrictions on use in
chemigation applications. If any fertilizer or chemicals
are applied through the system, a check valve or proper
back-flow prevention devices are required to ensure that
no contamination of the water source is possible.
were applied in the bed as starter fertilizer, then 80 lb.
would be injected through the season.
Sources
Several sources of N and K can be used for drip
irrigation injection, but all sources must be highly water
soluble to be effective. Nitrogen sources include
ammonium nitrate, calcium nitrate, various N solutions,
and urea. Potassium can come from potassium nitrate,
potassium chloride, or potassium sulfate.
Preplant Fertilizer
Take a soil test to know what level of fertility is in your
soil. Use a starter fertilizer, a small amount of fertilizer,
either liquid or dry, that is applied in the bed in drip
irrigated crops. This fertilizer would contain all of the
phosphorus (P) and micronutrients and up to 20-30% of
the nitrogen (N) and potassium (K). On soils testing
very low in P and K, the starter can be broadcast or
banded in the bed. If only small amounts of P and
micronutrients are required, then it would probably be
better to band these materials 2 to 4 inches below the
bed surface and to the side of the plant row but not
between the drip tube and the row. In most cropping
situations, approximately 20 to 30 lbs per acre of N and
K would be sufficient in the starter fertilizer mixture. In
situations where the soil test index for P is high or very
high, then no P would be added to the soil.
Frequencies
It is most convenient to think of rate of injection in
terms of pounds of a particular nutrient per acre per day
or week. For example, the recommended schedule of N
injection for a particular crop might be to start out early
in the season with l lb. N/acre/day and finally inject 2.5
lb./acre/day when the crop is at its peak growth rate.
The general rule is that the amount of N and K injected
/day or week starts out low and peaks with the crop
demand for the nutrients. It is tied to the stage of crop
growth or development.
Nutrients can be injected into the system in various
frequencies. Basically, the frequency of injection,
whether once a day or once every 2 days or even once a
week, depends on system design constraints, on soil
type, and on grower preference. Research has shown
that the frequency, even up to once per week, is not as
important as achieving a correct rate of application of
nutrients to the crop during a specified period of time.
With computer control of drip irrigation systems, some
growers find it easy to inject more frequently, such as
once every day. This may have a slight advantage
logistically. For example, injecting fertilizer on a more
frequent basis would reduce the chances that nutrients
were leached from the beds during a heavy rain storm
or excessive irrigation compared to injecting larger
amounts on a less frequent basis. If the chances for
leaching losses are extremely low for any particular field,
then injection once per week would be satisfactory. In
any case, it is extremely important that the nutrients
applied in any irrigation event are not subject to
leaching either during that same irrigation event or by
subsequent irrigation events. This is why knowledge of
the crop root zone is important for optimum fertilizer
management. It is critical to monitor the application of
water and to realize that fertilizer application is linked
closely to water application. To be a good fertigator,
a grower first needs to be a good irrigator.
Note on phosphorous and micronutrients. In general,
simultaneous application of P and micronutrients is not
recommended in drip irrigation systems. This is because
of precipitation events that can happen between the
fertilizers or between the P and the calcium or
magnesium in the well water. If application of P is
required during the season (such as during cold
periods), it should be injected as phosphoric acid alone,
in separate applications. Acidification of the irrigation
water to pH 4.0 to 5.0 might be needed to keep the P in
solution during this fertilizer application. Acidification
can be achieved by using phosphoric, sulfuric,
hydrochloric, or other acids to reduce the pH of the
water. Concentrated acids always must be added to
water, never the reverse.
Similar problems also occur for micronutrient injection.
The key is to avoid precipitation. If micronutrients must
be injected, then soluble forms, less subject to
precipitation, such as chelates, should be used. Like P,
micronutrients should be injected alone.
Injected Fertilizer Rates
In most situations, injected fertilizers will consist only
of N and K. The amount of N to use is determined
basically by the N requirement of the particular crop.
This amount of N is recommended for each crop for
each season. The current recommendations for opensoil culture can serve as “starting points” for developing
local plasticulture recommendations.
When injecting fertilizer in noncontinuous (bulk)
fashion, such as once per day or once per week, it is
important to keep in mind a few pointers about the
operational sequences for the injection events. The drip
irrigation systems always should be brought up to
operating pressure prior to injecting any fertilizer or
chemical. After the system has been pressurized fully,
the fertilizer can be injected. Following the completion
of the fertilizer injection, the drip irrigation system
should be operated for a period of time to ensure
The amount of K to be injected is based on the soiltest predicted requirement of K for the crop minus the
portion of this requirement that is applied in the bed as
a starter. For example, if the soil tested medium in K,
perhaps only 100 lb. per acre of fertilizer would be
required for the season. If 20% of this K, i.e., 20 lb.,
8
Crops Twilight
Barbecue & Ice Cream Social
flushing of the nutrients out of the tubes and into the
soil. This period might be the next irrigation cycle of the
day, if that water will not contain fertilizer. With these
operation constraints in mind, it becomes very important
to design the drip irrigation system so that fertilizer
injection can be achieved in a reasonable amount of
time without running the risk of overwatering the crop to
get the fertilizer applied. This means that injection
pumps, pipe sizes, and injection rates must be adjusted
properly to apply the nutrients in the desired amount of
time, so that the system can still be flushed without
applying excess water during the injection and
subsequent cycles.
CMREC Upper Marlboro Farm
August 2, 2012
You are invited to attend a Field Crops Research
Twilight, Barbecue and Ice Cream Social at the
Central Maryland Research &
Education Center, Upper
Marlboro Farm on Thursday,
August 2, 2012 from 4:30 pm
to 9 pm. A barbecue dinner will
be served at 4:30 pm followed by
homemade ice cream prior to the
evening tour!
In some systems, fertilizer is injected continuously
(concentration injection) so that all irrigation water
applied contains nutrients. This system is acceptable as
long as no irrigation cycle is excessive, causing nutrients
to be leached below the root zone.
The research farm is located at
2005 Largo Road, Upper Marlboro, Maryland.
It should be apparent from the above discussions that
water application and fertilizer application are linked
inextricably.
University of Maryland Extension Educators and
Specialists will showcase their field crop, vegetable and
fruit research plots.
Barbecue Begins at 4:30
Ice Cream Served at 5:15
Public Meetings for
Maryland’s Proposed
Changes to Nutrient
Management
Regulations
Crops Twilight at 6:00
¾ Please arrive on-time as the tour will start
promptly at 6:00 pm. This event is free.
However, a reserved meal ticket is required.
If you need special assistance to participate, please
contact the Anne Arundel County Extension office at
410-222-6759 by August 1, 2012.
For full meeting details, and registration information
contact any of the Southern Maryland Extension offices.
For more information contact David Myers at the Anne
Arundel County Extension office at 410-222-6759.
The Maryland Department of Agriculture (MDA) will
host a series of public meetings across the state to
provide information to farmers, environmental
interests, local governments and other stakeholders on
proposed changes to Maryland’s Nutrient Management
Regulations and offer an opportunity for public
comment. MDA will hold public meetings in four
locations around the state. All meetings will be held
from 7:00 p.m. to 9:00 p.m. at:
Western Maryland
Wednesday, July 18, 2012
Washington County Agricultural Education Center
7313 Sharpsburg Place
Boonsboro, MD 21733
Cut Flower Tour
August 6, 2012
8:30 a.m. to 3:30 p.m.
Eastern Shore
Monday, July 23, 2012
Talbot Community Center
10028 Ocean Gateway
Easton, MD 21601
Tour Stop Locations:
1) M and M Plants Dickerson, MD
2) Farmhouse Flowers and Plants Brookeville, MD
Sponsored by:
University of Maryland Extension
In cooperation with:
Maryland Greenhouse Growers’ Association
Association of Specialty Cut Flower Growers
See the attached Flier For more information.
Southern Maryland
Wednesday, July 25, 2012
Calvert County Fairgrounds
140 Calvert Fair Drive
Prince Frederick, MD 20610
9
Vegetable & Fruit Headline News
A bi-weekly publication for the commercial vegetable
and fruit industry available electronically in 2012 from
April through September on the following dates: April12 &
26; May 10 & 24; June 7 & 21; July 12 & 26; August 16; September 6
Published by the University of Maryland
Extension Agriculture and Natural Resources
Profitability Impact Team
Organic Vegetable Field Day
Submit Articles to:
Editor,
R. David Myers, Extension Educator
Agriculture and Natural Resources
7320 Ritchie Highway, Suite 210
Glen Burnie, MD 21061
410 222-6759
Where: Upper Marlboro Research and Education Center
(2005 Largo Rd, Upper Marlboro, MD 20774)
When: Thursday August 9 from 5-8:30 pm. Dinner at
5:30 and tour starts at 6:30 pm.
myersrd@umd.edu
Who: Anyone interested in organic vegetable production
Article submission deadlines for 2012:
April 11 & 25;
May 9 & 23; June 6 & 20; July 11 & 25; August 15; September 5
What: Topics will include use of Compost tea for plant
health and pest management, value of cover crops and
manure in a fertility program, changing the soil microbial
population for better crop production, weed control and
management, companion planting for pest management,
cucumber beetle control, along with other topics.
Note: Registered Trade Mark® Products, Manufacturers, or Companies
mentioned within this newsletter are not to be considered as sole
endorsements. The information has been provided for educational
purposes only.
Contact Jerry Brust for full program details at:
jbrust@umd.edu or 301-627-8440
See the Attachments!
10
University Of Maryland Extension
11975 Homewood Road
Ellicott City, MD 21042
Directions to M and M Plants (16415
Comus Road, Dickerson, MD 20842)
From I-270: Take exit 18 and merge onto MD
121 N Clarksburg Road toward Clarksburg.
Take the first left onto MD 355 N Frederick
Road. Go 1 mile and turn left onto Comus
Road. The farm will be 2.5 miles on the right.
Directions to Montgomery County
Extension office (18410 Muncaster Road,
Derwood, MD 20855) from M and M Plants
Turf left out of driveway. Follow for 2.5 miles
to MD-355/Frederick Road. Follow for 3.5
miles and make slight left onto Brink Road.
Follow for 2.7 miles and make slight right onto
Wightman Road. Follow for 1.4 miles and
continue on Snouffer School Road. Follow
for 2.6 miles and continue onto MD 115 E/
Muncaster Mill Road. In 1.3 miles turn left onto
Muncaster Road. In 1.3 miles turn left into
entrance and follow along the left fork of the
drive to the parking at the top of the hill.
Directions to Farmhouse Flowers and
Plants (4501 Gregg Road, Brookeville, MD
20833) from Extension office
Go left out of the driveway and follow for about
2 miles. Turn right onto Route 108. In a tenth
of a mile, turn left onto Brookeville Road.
Follow for 0.5 miles and turn left onto Zion
Road. Follow for 1.8 miles and turn right onto
Gregg Road. The farm will be about a tenth of
a mile on the left.
University of Maryland Extension programs are open to
all citizens without regard to race, color, gender, disability, religion,
age, sexual orientation, marital or parental status,or national origin.
Cut Flower Tour
August 6, 2012
8:30 a.m. to 3:30 p.m.
Locations
M and M Plants
Dickerson, MD
Farmhouse Flowers and Plants
Brookeville, MD
Sponsored by
University of Maryland Extension
In cooperation with:
Maryland Greenhouse Growers’
Association
Association of Specialty Cut Flower
Growers
1:30 – 1:45 Travel to Farmhouse
Flowers and Plants, Brookeville, MD
Weed Control. Chuck Schuster, Montgomery
County Office, University of Maryland Extension
Tour of Farmhouse Flowers and Plants: Dave
Dowling
Farmhouse Flowers & Plants cut flower
operation will be the afternoon tour site. Dave
Dowling’s Farmhouse Flowers is always cutting
edge with their production methods and new
cultivars. Dave will share his experiences and
insights with cut flower production.
For more information on the program:
301-596-9413
__________
Total Payment Enclosed
________________________________________________
________________________________________________
________________________________________________
Names of Registrant (s): (please print clearly)
Outstanding Cut Flowers Grown at Long
Season Statice Farm. Ron Peterman will
highlight some of his new and outstanding cut
flowers that he is growing at his farm.
MC
Visa
Discover American Express
Payment Amount: _________
Credit Card #: _______________________________
Expiration date: ________ Security code: _____
Name on card: ______________________________
Signature of cardholder:_______________________
You can also fax your registration with credit card info
to 410-531-2397.
What Insects Are Stalking Your Cut Flowers
in 2012? Stanton Gill, Central Maryland
Research and Education Center, University of
Maryland Extension
(need to preregister to guarantee lunch)
Phone:_______________ Email:_________________
Tour of M and M Flowers: Madgie and Mark
McGaughan
M and M Plants is a local business and sells
cut flowers, bedding plants, and vegetable
starts mainly at farmers markets. They
provide flowers for weddings and other events
in season. Houseplants are a year round
business while the cut flowers and bedding
plants are seasonal.
Lunch: Montgomery County Extension office
City:________________ State:____ Zip Code:_____
Lunch and an indoor talk will be at the
Montgomery County Extension office followed
by a tour and talk at nearby Farmhouse
Flowers and Plants.
11:30 – 12:15 Travel to Montgomery
County Extension Office, Derwood, MD
Cost: $25 per person by July 30th
$30 per person after July 30th (Lunch not guaranteed)
M and M Plants is nestled in the foothills of
Sugar Loaf Mountain in Upper Montgomery
County. M and M Plants uses both field and
high tunnel production to produce their cut
flowers.
Address:____________________________________
For the first time M and M Plants will “open
their doors” for other cut flower growers to
come and see how they produce quality cut
stems for their farm markets.
Company:___________________________________
ASCFG New Variety Trials by Growers.
Madgie McGaughan and Leon and Carol
Carrier, Plantmasters, Inc. will highlight some of
the varieties that are a part of the Association of
Specialty Cut Flowers Growers (ASCFG) grower
trials. They will let you know what they think
worked and what didn’t.
August 6th Cut Flower Farm Tour
11975 Homewood Road
Ellicott City, MD 21042
What better thing is there to do in
August then to visit other people’s cut
flower operations?
Send to:
Deadly Diseases of Cut Flowers. Dave
Clement, Home and Garden Information Center,
University of Maryland Extension
August 6, 2012 Cut Flower Tour Registration Form Please make checks payable to: “University of Maryland”
Registration/Check-in
begins at 8:30 a.m.
Tour starts at 9:00 a.m.