PROCEEDINGS
SOUTHERN WEED SCIENCE SOCIETY
NEW CENTURY: New Opportunities
55th Annual Meeting
Servicing Agriculture In:
ALABAMA
ARKANSAS
FLORIDA
GEORGIA
KENTUCKY
LOUISIANA
MISSISSIPPI
MISSOURI
NORTH CAROLINA
OKLAHOMA
SOUTH CAROLINA
TENNESSEE
TEXAS
VIRGINIA
PUERTO RICO
January 28, 29, and 30, 2002
Hyatt Regency
Atlanta, Georgia
ISSN:0362-4463
2002 Proceedings, Southern Weed Science Society, Volume 55
Preface
PREFACE
These PROC EEDING S of the 55th Annual Meeting of the Southern Weed Science Society contain papers and abstract
of presentations made at the annual meeting. These papers and abstracts are indexed according to subject matter and
authors. A list is also included giving the common a nd trade or co de nam es, chem ical names and manufacturers of all
herbicides mentioned in the publication. Other information in these PROCEED INGS includes: biographical data of
recipients of the SW SS D istinguished Service, Outstanding E ducator, O utstanding Young W eed Scientist, and
Outstanding Graduate Students awards; the RESEARCH REPO RT; lists of officers and committee members; minutes
of all business meetings; and lists of registrants attending the annual meeting, sustaining mem bers, charter membe rs,
and contributors to the SWS S Endowment Foundation.
Only papers presented at the m eeting and subm itted to the Editor in the prescribed form at for printing are included in
the PRO CEE DING S. Papers may be up to five pages in length and abstracts are limited to one page. Papers and
abstracts exceeding these limits will be published but the authors will be charged $15 per page for each paper the
contribution exceeds these limits. Invitational papers are not subject to these page charges.
Autho rs are required to submit an original, two copies and a diskette copy of the file prepared according to the prescribed
format. If a contribution is not submitted in a suitable form for publication, it may be retyped by the Editor at a charge
of $25.00 or it may not be printed in the PROCEED INGS. Some papers may be returned to the author for retyping if
time permits.
The use of commercial names in the PROCEED INGS does not constitute an endorsement, nor does the non-use of
similar products constitute a criticism, by the Southern Weed Science Society.
Additional copies of the 2002 PROCEED INGS and of some prior year editions of the PROCEEDINGS AND
RESEARCH REPORTS are available. Also, copies of the SWSS RESEARCH METHODS IN W EED SCIE NC E (3 rd
edition, 1986 ), and the SW SS W EED ID EN TIFIC AT ION GU IDE S are available. This docu men t is also av ailable in
PDF format at the SW SS w eb site (ww w.sw ss.ws). For information concerning the availability and cost of these
publications, contact Mr. R. A. Schm idt, Business Manag er, Southe rn W eed S cience Society, 1508 W est University
Avenue, Champaign, IL 61821-3133.
Peter A. Dotray, Editor
Southern W eed S cience Society
About this file: This file was created by scanning the printed publication.
software have been corrected; however, some mistakes may remain.
i
Misscans identified by the
2002 Proceedings, Southern Weed Science Society, Volume 55
–
Section IV
by
Taonly)
Readc Arble 2.cover(herbaceous
Averageobservation
percent clear
of gtime
round
Time of Observation
No
TReaadrt.
April
August
1
100a
2
100a
3
99a
4
100a
September
5
100a
6
99a
October
7
100a
8
100a
9
100a
10
100a
11
28b
1Values in a column followed by
May
June
July
August
percent
100a
100a
98a
99a
98a
97a
97a
98a
98a
93a
93a
95a
82a
50b
76a
67ab
99a
98a
96a
94a
93a
86a
38b
39b
97a
96a
41b
41b
0c
0.05
67ab
76a
15c
15c
0c
100a
100a
96a
97a
2b
the same letter do
98a
96a
86a
72b
0c
not differ at � =
Table 3. Percent reduction of principal woody species in 2000 DuPont Fall Oust study – Mississippi
Species1
Trt. No
SWG
REM
BLC
Trees
percent
1
100.0a2
100.0a
96.7a
97.7a
2
100.0a
96.3a
100.0a
95.9a
3
100.0a
100.0a
100.0a
100.0a
4
98.3a
93.3a
93.3a
90.0a
5
100.0a
100.0a
100.0a
93.5a
6
91.7a
93.3a
100.0a
87.0a
7
97.8a
95.8a
00.0a
97.1a
8
100.0a
94.9a
87.8a
87.3a
9
100.0a
100.0a
88.3a
95.6a
10
100.0a
100.0a
100.0a
93.9a
11
50.6b
41.7b
-133.3b3
15.1b
(Average all reps).
Total
89.3a
81.5ab
91.1a
83.5ab
82.4ab
62.2b
76.2ab
79.1ab
85.6ab
88.2ab
0.4c
1
FIRST-YEAR WOODY PLANT CONTROL FOLLOWING SEVERAL FORMULATIONS AND TIMINGS
OF GLYPHOSATE WITH OR WITHOUT IMAZAPYR. T.B. Harrington, A .W . Eze ll, J.L. Ye iser, and J.O. Cobb;
University of Georgia, Athens, GA 30602, Mississippi State University, Starkville, MS 39762, Stephen. F. Au stin State
University, Nacogd oches, TX 75962, and Dow AgroSciences, Auburn, AL 36830. 1
ABSTRACT
Several formulations of glyph osate were applied with or without imazapyr in June and October 2000 at sites located in
Geo rgia, M ississipp i, and Texas. The objective of the research was to comp are control of woody species betwee n
experimental and conventional formulations of glyphosate with or without imazapyr. Percentage change in total length
of woody stems was evaluated immediately before treatment and one year following treatment. In genera l, the
experimental formulations of glyphosate provided similar levels of woody con trol as that observed for Accord ® SP or
generic glyphosate. Woody control from Accord ® SP was often greater than that observed from generic glyphosa te ,
especially at the Georgia site.
1
This research was supported by financial and in-kind assistance from the Monsanto Corporation. The authors thank the
Timber Company and other members of forest industry for providing study sites for the research.
78
2002 Proceedings, Southern Weed Science Society, Volume 55
Section IV
INTRODUCTION
In 2000, several new formulations of glyphosate were being developed by the Monsanto Corporation prior to their sale
of the Accord ® line of products to Dow AgroSciences. In this study, three new formulations of glyphosate with or
without imazapyr were compared to currently labeled products applied at the same rate, including combinations of
Accord ® SP and generic glyphosate applied with or without Chopper ® or Arsenal® AC.
METHODS AND MATERIALS
The study was conducted at three study sites in the southeastern U.S.: Oglethorpe County GA, Winston County MS,
and Angelina County TX. Soil types include a sandy clay loam in Georgia, a silty clay loam in Mississippi, and a sandy
loam in Texas. Pine or mixed pine-hardwood stands were harvested at each site one to two years prior to study initiation
resulting in a relatively uniform coverage of hardwood and shrub sprouts. At each site, 48 plots of dimension 30’ x 100’
were permanently marked. Seven herbicide treatments (Table 1) and an untreated check applied at each of
design (Georgia) or a randomized complete block design (Mississippi and Texas) with three replications of each
treatment. Treatments were applied with a CO 2 backpack-pole sprayer fitted with a KLC9 nozzle to apply a uniform
spray swath approximately 30’ wide. Spray volume was 15 gallons per acre.
Immediately before and one year following treatment, total length of woody stems was assessed for each woody species
within a centrally located 10’- x-80’ area in each plot. Stems were counted according to each of seven 1-ft. height
classes between 1.5’ and 9.5’. Total stem length was calculated per species by multiplying each stem frequency by its
respective height-class midpoint and summing these products for each plot. Percentage change in total stem length
(hereafter referred to as stem reduction) was calculated as 100*(T01-T00)/T00, where T00 and T01are total stem
lengths in 2000 and 2001, respectively, for a given plot and species.
For each species having adequate representation among treatments, data were subjected to analysis of variance to
determine if stem reduction varied significantly (c=0.05) among months and treatments. Duncan’s Multiple Range Test
was used to conduct multiple comparisons of treatment means.
RESULTS AND DISCUSSION
Woody plant responses to the herbicide treatments varied considerably among the study sites. Woody plant control was
excellent for most of the herbicide treatments at the Georgia and Mississippi sites, especially for the October treatments
(Tables 2-3). At the Georgia site, stem reduction for sweetgum (Liquidambar styraciflua) was greater for October
treatments than for June treatments, while the reverse trend was true for black cherry (Prunus serotina). At the Texas
site, stem reduction of yaupon (Ilex vom itoria) was greater for June treatments than for October treatments (Table 4).
No clear timing differences were detected at the Mississippi site.
In general, the dry ammonium salt of glyphosate (MON 78015) plus Chopper ® provided an equivalent level of stem
reduction as Accord ® SP plus Chopper ® (treatment 2 versus treatment 1). Stem reduction from Accord ® SP was often
greater than that observed from generic glyphosate plus X-77 ® surfactant (treatment 3 versus treatment 6), especially at
the Georgia site. The glyph osate and imazapyr blend (MON 78229) provided similar or slightly better control of woody
stems as the generic glyphosate plus Arsenal® AC treatment (treatment 4 versus treatment 5). The ether amine
formulation of glyphosate (MON 78128) provided similar to slightly lower levels of control as that observed for generic
glyphosate (treatment 7 versus treatment 5).
Results indicate that woody stem control from the new formulations of glyphosate do not differ markedly from that
observed from conventional combinations of Accord ® SP, Chopper ® , or Arsenal® AC. In addition, Accord ® SP may
provide a higher level of woody control as generic glyphosate plus X-77 ® surfactant on specific sites.
79
2002 Proceedings, Southern Weed Science Society, Volume 55
Section IV
TABLES
Table 1. Formulations and rates of herbicides and surfactant applied in June and October 2000 to control woody
vegetation at study sites in Georgia, Mississippi, and Texas.
Trmt.
Glyphosate
Glyphosate rate
Imazapyr
Imazapyr rate
Surfactant
Surfactant
formulation
formulation2
rate
no.
1
Accord ® SP
5 lbs. a.i./acre
Chopper ®
0.31 lbs. a.i./acre
0.31 lbs. a.i./acre
2
MO N78015
5 lbs. a.i./acre
Chopper ®
®
8 lbs. a.i./acre
3
Accord SP
4
MO N78229
6 lbs. a.i./acre
0.19 lbs. a.i./acre
X-77 ®
2.5% by vol.
5
Generic
6 lbs. a.i./acre
Arsenal® AC
2.5% by vol.
6
Generic
8 lbs. a.i./acre
X-77 ®
0.19 lbs. a.i./acre
7
MO N78128
6 lbs. a.i./acre
Arsenal® AC
2
MO N78015 is a dry ammonium salt of glyphosate. MO N78229 is a glyphosate and imazapyr blend with the same rates
of active ingredients as found in treatment 5. Generic glyphosate is a product that is 54% active ingredient. MO N78128
is an ether amine salt of glyphosate plus surfactant.
Table 2. Percentage change in total stem length of several hardwood species one year following seven herbicide
treatments and an untreated check at the Georgia study site. For each timing, means within a column followed by the
same letter(s) do not differ significantly (P>0.05).
Timing
Treatment
number
June
1
2
3
4
5
6
7
untreated
check
October
1
2
3
4
5
6
7
untreated
check
Species
red maple
sweetgum
black cherry
white oak
water oak
---------------------------- % change in total stem length -----------------------------­
-100.0c
-93.6a
-100.0b
-100.0b
-95.3cde
-100.0c
-96.2a
-100.0b
-100.0b
-100.0e
-99.7c
+18.1a
-100.0b
-100.0b
-62.6bc
-100.0c
-87.9a
-100.0b
-100.0b
-97.8de
-98.4c
-34.8a
-100.0b
-100.0b
-74.4bc
-61.0ab
+164.5a
-100.0b
-85.2a
+42.2ab
-85.9b
-77.4a
-100.0b
-100.0b
-90.5cd
-13.0a
+192.7a
-45.1a
-13.4a
+306.3a
-97.2b
-100.0b
-100.0b
-100.0b
-100.0b
-95.5b
-100.0b
+62.1a
-96.3b
-98.5b
-96.4b
-98.1b
-97.9b
-97.2b
-91.3b
+62.9a
-72.2a
-100.0a
-96.4a
-97.3a
-100.0a
-96.9a
-95.0a
-71.4a
80
-100.0b
-100.0b
-100.0b
-100.0b
-100.0b
-100.0b
-100.0b
-79.8a
-97.9b
-100.0b
-99.2b
-97.1b
-97.9b
-96.7b
-89.9b
+134.3a
2002 Proceedings, Southern Weed Science Society, Volume 55
Section IV
Table 3. Percentage change in total stem length of several hardwood species one year following seven herbicide
treatments and an untreated check at the Mississippi study site. Means within a column followed by the same letter(s)
do not differ significantly (P>0.05).
Timing
June
October
Treatment
number
1
2
3
4
5
6
7
1
2
3
4
5
6
7
untreated
check
Species
all species
combined
sweetgum
red maple
post oak
black gum
----------------------------- % change in total stem length -----------------------------­
-93.0a
-93.3a
-87.5a
-100.0a
-84.0a
-64.3b
-100.0a
-100.0a
-100.0a
-93.0a
-97.0a
-100.0a
*
-80.0ab
-85.3a
-100.0a
-96.3a
-100.0a
-85.7a
-92.3a
-100.0a
-94.7a
-97.0a
*
-87.3a
-92.7a
-97.0a
-91.3a
-80.0ab
-81.3ab
-100.0a
-94.0a
-87.7a
*
-78.3b
-62.7b
-78.0a
-100.0a
-100.0a
-89.7a
-98.0a
-87.7a
-100.0a
-100.0a
-94.0a
-100.0a
-90.0a
-100.0a
-60.9b
-76.3b
-100.0a
-83.3a
-100.0a
-100.0a
-90.3a
-97.3a
-66.7ab
-100.0a
-100.0a
-89.0a
-98.3a
-72.0ab
-100.0a
-5.0c
-70.7b
-98.7a
-66.7ab
-100.0a
-81.3a
-84.3a
-18.0c
-53.3b
-25.0c
*
+25.3c
Table 4. Percentage change in total stem length of several hardwood species one year following seven herbicide
treatments and an untreated check at the Texas study site. For each timing, means within a column followed by the
same letter(s) do not differ significantly (P>0.05).
Timing
Treatment
number
June
1
2
3
4
5
6
7
untreated
check
October
1
2
3
4
5
6
7
untreated
check
Species
yaupon
southern red oak
sweetgum
------------------------ % change in total stem length -------------------------­
-87.0a
-11.0ab
-3.0b
-42.0b
-12.0ab
-10.0b
-40.0b
-2.0b
-4.0b
-65.0ab
-5.0ab
-10.0b
-62.0ab
-19.0ab
0.0b
-57.0ab
-35.0a
-27.0a
-73.0ab
-29.0ab
-15.0ab
+6.0
-41.0
-8.0
-49.0ab
-44.0ab
-73.0a
-72.0a
-29.0b
-30.0b
-26.0b
+6.0
-17.0b
-64.0a
-15.0b
-18.0b
-12.0b
-19.0b
-16.0b
-40.0
-12.0a
-6.0a
-3.0a
-8.0a
-18.0a
-12.0a
0.0a
-10.0
SECOND-YEAR EVALUATION OF RESPROUT POTENTIAL FOLLOWING BASAL HERBICIDE
APPLICATIONS TO VARIOUS BRUSH SPECIES. L.R. Nelson and A .W . Ezell. Clemson University, Clemson,
SC, and Mississippi State University, Mississippi State, MS.
ABSTRACT
Dormant season basal sprays were applied to the lower 46 cm of sweetgum (Liquidambar styraciflua L.) and black
cherry (Prunus serotina Ehrh.) stems in South Carolina and to pecan (Carya illinoensis), green ash (Fraxinus
pennsylvanica Marsh.), and cherrybark oak (Quercus falcata var. pagodaefolia Ell.) in Mississippi. Herbicides were
mixed as a % V/V in Hygrade EC ( petroleum based carrier with emulsifiers). Treatments included 25% triclopyr
81