Download - Peanut Weed Management Update 2008
Peanut Weed Management Update 2008
Eric P. ProstkoExtension Weed Specialist
Department of Crop & Soil SciencesThe University of Georgia
Topics For Discussion
• Resistance Update
• Modes of Action Info
• Aim – Harvest Aid label
• Palmer Amaranth
• Herbicide/Fungicide Tank-mix Issues
– Provost
• 2,4-DB issues
• Classic Update
GA Confirmed Glyphosate-Resistant Palmer SitesGA Confirmed Glyphosate-Resistant Palmer Sites
2005
2006
Current Testing2007
GA Confirmed ALS-Resistant Palmer SitesGA Confirmed ALS-Resistant Palmer Sites
Herbicide Modes of Action Info
• New Table in 2008 Pest Control Handbook
• MOA’s listed in crop sections
• www.gaweed.com
diclosulam (Strongarm) 84WG 0.45 oz
0.024 Provides general broadleaf weed control. Incorporate into top 1-3" of final seedbed. Goodto excellent control of many species includingbristly starbur, wild poinsettia, eclipta, andcopperleaf. Should be tank-mixed with a grassherbicide. Poor control of sicklepod. Controlof nutsedge has been variable and inconsistent. Can also be applied preemergence. Croprotation restrictions: cotton = 10 months;soybeans = 0 months; wheat, barley = 4months; oats, rye = 6 months; corn = 18months (10 months - IR hybrids); tobacco,sorghum = 18 months; other crops = 30months. MOA = 2.
• September 2007
• 1-2 oz/A
• NIS or COC
• 7 day PHI
• Morningglory
• Pigweed
• Spiderwort
Harvest Aid Label
Managing Palmer Amaranth• Know the enemy
– Lots of seed– Grows 1-2”/day– Very competitive
• Resistant or not??– ALS or GR
• Residual herbicide– Activation
• irrigation or incorporation
• Timely POST’s
• Avoid overusing PPO’s
Palmer Amaranth Control in Peanut with PRE Herbicides
0
20
40
60
80
100
11 18 23 38 53 94
Time (DAT)
Cont
rol -
%
.
Valor Dual Magnum Stalwart Outlook
Valor @ 3 oz/ADual Magnum @ 1 pt/AStalwart @ 1 pt/AOutlook @ 1 pt/A
Palmer Amaranth Control in PeanutsMacon County, GA – 2007 (38 DAT)
NTC Valor SX 51WG @ 3 oz/A
Palmer Amaranth Control in PeanutsMacon County, GA – 2007 (38 DAT)
NTC Dual Magnum 7.62EC@ 1 pt/A
Residual Herbicides Must Be Activated!!!!!!
• Rainfall• Irrigation• Herbicide incorporation
– Conventional tillage– Dryland fields– No chance of rain– will help but not a guarantee– 2X, angle– Some herbicides should not
be incorporated• Valor
This is what a 2” pigweed looks like!!!!
Provost (10.7 oz/A) + Fulbor + Penatrator Plus + 2,4-DB
Richard McDaniel, 2007
Probable Provost Label Changes
• No surfactants
• No tank-mixes with 2,4-DB
• No tank-mixes with EC pyrethroids
• Others??
Herbicide/Fungicide Tank-Mixeshttp://www.peanut.ncsu.edu/ag653_web.pdf
• Possible combinations are endless
• Avoid 3-way mixes if possible
• Regional Publication
– AGW-653
– NCSU
– Updated in May 2007
Contaminated Lots
• Contamination if exceeds 250 ppm• Tested Lots
– FB-01 = 2,4-D acid (0.294%)– EC-16 = dicamba (0.17%) + 2,4-D acid
(0.11%)– EC-16 = Dicamba (0.198%) + 2,4-D acid
(0.104%)– EL-31 = 101-117 ppm 2,4-D (3 samples)– CE-04 = 56 ppm of 2,4-D
What will 2,4-D and dicamba do to peanuts????
• Research in GA conducted over the past few years would suggest that 2 oz/A of 2,4-D would not cause many problems.– If contaminated product was applied at
24 oz/A then 2,4-D rate would only be 0.05-0.18 oz/A.
What will 2,4-D and dicamba do to peanuts????• No data exists for peanut response to
dicamba.– Peanuts are more sensitive to dicamba
than 2,4-D.– Dicamba rate was equivalent to 0.08-
0.1 oz/A (Normal rate for corn is 8 oz/A)
Why is this important?
• Peanut response to dicamba
– Dicamba resistant crops are in the pipeline
– More contamination/drift problems are likely
Classic/Peanut Issues
• How much does it really effect TSWV?
• How much does it really influence yields?
Classic Research in Georgia
• 2000-2007• 15 locations• 6 varieties
– GA Green, GA-02C, GA-03L, AP-3, C-99R, AT-201
• weed-free trials• Results
– No interaction between variety and Classic timing
– TSWV increased an average of 9%– No effect on peanut yield
The Influence of Classic on the Incidence of TSWV (2000-2007)
28
3537
34 3430
0
8
16
24
32
40
NTC 60-69 70-79 80-89 90-99 100+
Classic Timing (DAE)
TSW
V (%
) .
Classic @ 0.5 oz/A + NIS @ 0.25% v/vAveraged over 6 varieties and 15 locations*Significantly different from NTC (P = 0.05.)
* **
The Influence of Classic on Peanut Yield (2000-2007)
41853844 3728
4820
39943670
0
1000
2000
3000
4000
5000
NTC 60-69 70-79 80-89 90-99 100+
Classic Timing (DAE)
lbs/
A .
Classic @ 0.5 oz/A + NIS @ 0.25% v/vAveraged over 6 varieties and 15 locationsP = 0.3321
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