2007 corn weed control update
DESCRIPTION
2007 Corn Weed Control Update. Eric P. Prostko Extension Weed Specialist Department of Crop & Soil Sciences - UGA. Changes in 2007 Pest Control Handbook. Added Sequence Added Expert - PowerPoint PPT PresentationTRANSCRIPT
2007 Corn Weed 2007 Corn Weed Control UpdateControl Update
Eric P. Prostko
Extension Weed Specialist
Department of Crop & Soil Sciences - UGA
Changes in 2007 Pest Control HandbookChanges in 2007 Pest Control Handbook
Added Sequence Added Expert Added generic metolachlors but still included the following
warning: The generic formulations of metolachlor (Parallel, Stalwart, Me-Too-Lachlor) have not provided the same length of residual control of certain weeds as similar rates of Dual Magnum formulations in some UGA field trials.
Added Firestorm Added rain-free periods Added a burndown table for reduced tillage. Added Propel Post-harvest control rec's for tropical spiderwort Table of metolachlor and s-metolachlor products Added Callisto to POST section Table for ALS/GR-resistant pigweed
Burndown Control OptionsBurndown Control Options
glyphosateParaquatIgnite (glufosinate) tank-mixes with?
2,4-D atrazine
Need a clean seed-bed at planting
Ryegrass Control - BurndownRyegrass Control - Burndown
Hard to kill with 1 shot Option # 1
Glyphosate @ 1.125 lb ae/A + atrazine @ 3 pts/A
Option #2 Gramoxone Inteon @ 1.9
pts/A – 2 WBP fb Gramoxone Inteon @ 1.9 pts/A + atrazine @ 3 pts/A - planting
RR corn systems Accent????
Conventional or RR Systems?Conventional or RR Systems?
Conventional SystemsConventional Systems
Atrazine still THETHE major player in any system
Prowl in cheap but …….
One of my favorites is Accent + AtrazineIf Texas panicum is main problem
many Pre-mixes
Why do you not want to spend the money on an AccentWhy do you not want to spend the money on an Accent + Atrazine treatment in field corn? + Atrazine treatment in field corn?
168
113
0
40
80
120
160
200
Bu/
A
Accent + Atrazine Untreated
Data from 18 irrigated weed control trials conducted in Georgia from 2001-2006.At $2.00 to 3.00/bu, it only takes a 9 to 14 bu/A increase to pay for the treatment!!!
Corn Yield Response to Various POST Corn Yield Response to Various POST Herbicide TreatmentsHerbicide Treatments
131
95
179
139
193207
184
212
0
50
100
150
200
250
low (11/ft2) high (27/ft2)
Texas Panicum Density
Bu/
A
Untreated Prowl Accent RR-split
Average of 2 tests conducted in 2003 and 2004 (Tifton, Attapulgus)Average of 2 tests conducted in 2003 and 2004 (Tifton, Attapulgus)Where Texas panicum is the main weed problemWhere Texas panicum is the main weed problemAtrazine PRE @ 1.5 qt/AAtrazine PRE @ 1.5 qt/A
e
d
ab a
b
a aa
Conventional Weed Management SystemsConventional Weed Management SystemsMany Pre-Mixes AvailableMany Pre-Mixes Available
Bicep II Magnum (atrazine + Dual II Magnum) Lariat/Bullet (atrazine + Lasso) Lexar (atrazine + Dual Magnum + Callisto) many others preemergence a good choice if many different weed species are
present need 0.5” of rainfall or irrigation within 7-10 days
for activation
Post-Directed Options for Field CornPost-Directed Options for Field Corn
EvikGramoxone
Inteon/FirestormLorox/LinexAim
tropical spiderwortpigweedsmorningglory
Should you use the RR corn system?Should you use the RR corn system?
advantages Inexpensive easy Broad spectrum Reduced drift concerns No soil insecticide issues
disadvantages No residual over-reliance on a single
product Herbicide resistance
concerns Volunteer in other RR crops
How would I use RR corn systems?How would I use RR corn systems?
If you are unwilling to use a PRE application of atrazine or something else….
2 applications of glyphosate1st application: 21-28 DAP + atrazine (1.5-2.0 qt/A)2nd application: 35-40 DAP
SequenceSequence (s-metolachlor + glyphosate) ExpertExpert (s-metolachlor + atrazine + glyphosate) Do not forget to include extra seed costs/A in
your budgets! Irrigated @ 30,000/A = $12-13.00/ADryland @ 18,000/A = $7-8.00/A
Texas Panicum Control At Harvest with Single Texas Panicum Control At Harvest with Single or Split Applications of Roundup WM - IIor Split Applications of Roundup WM - II
CN-04-04 (Attapulgus)
UntreatedRoundup WM @ 22 ozs/A
21 DAP
Roundup WM @ 22 ozs/A21 + 35 DAP
125
164
181
0
30
60
90
120
150
180
210
Untreated Single Split
Bu/
A
Corn Yield Response to Single or Split Applications Corn Yield Response to Single or Split Applications of glyphosate (4.5 lb ae/gal) @ 22 ozs/A.of glyphosate (4.5 lb ae/gal) @ 22 ozs/A.
Average of 7 locations (2003-06)DKC67-60RR
Glyphosate Resistance Around the World (12 Glyphosate Resistance Around the World (12 species)species)
rigid ryegrass (1996) goosegrass (1997) horseweed (2000) Italian ryegrass (2001) hairy fleabane (2003) buckhorn plantain (2003) common ragweed (2004) giant ragweed (2004) Palmer amaranth (2005) common waterhemp (2005) johnsongrass (2005) wild poinsettia (2005)
** Can be found in the US
2005 GR-Pigweed Survey
47 of 100 sitesWith Confirmed Resistance to glyphosate!!
1 location in Lee CountyConfirmed in 2006
**
Preserving the Value of GlyphosatePreserving the Value of Glyphosate
tank-mix 2,4-D in burndown when glyphosate will be used in-cropConsider paraquat or Ignite if appropriate
Alternate glyphosate use with other herbicide modes of actionTank-mix with atrazine
Use other practices such as cultivation
Do not allow weed escapes to produce seed
New Products that have been testedNew Products that have been tested
Syngenta POST 3 oz/A + COC + UAN or AMS
($13-15/A) Up to 30” tall or 8-leaf corn Palmer amaranth up to 5” If 2,4-D is undesirable or ALS-
resistance Tank-mix with atrazine also good on horsenettle Interaction with OP’s
Texas Panicum ControlTexas Panicum Control
OR OR
•About 30% of the time, Accent has provided better control of Texas panicumAbout 30% of the time, Accent has provided better control of Texas panicum•But, yields have not been different.But, yields have not been different.
What about Liberty-Link Corn?What about Liberty-Link Corn?
GlufosinateLiberty (corn)Ignite (cotton)
No tech feeup to 24” tall corn or V7Tank-mix with atrazine
Liberty ATZ good on morningglory, Texas millet,
sicklepodHybrid performance???
Garst 8353CB/LL, Hytest 7729Hx/LL
2007 Rebate Program2007 Rebate Program* Up to $6.25/A* Up to $6.25/A
Don’t Forget Liberty-Link Corn!Don’t Forget Liberty-Link Corn!
Untreated Liberty 1.67SL @ 32 ozs/AAtrazine @ 90WG @ 1.0 lb/A
AMS @ 3 lbs/AApplied 26 DAP
CN-10-06 (Croplan Genetics 731 HX/LL)Ponder Farm52 DAP
83 Bu/A 114 Bu/A
Morningglory Control in CornMorningglory Control in Corn
as much atrazine as possible
1.0 lb/A – PRE fb 1.5 lb/A – POST small grain rotations tank-mix with Aim (POST)
2,4-D, Clarity Liberty-Link Corn Systems split applications of
glyphosate (RR corn)* 1st application + atrazine
Pigweed Control in CornPigweed Control in Corn preemergence
AtrazineDual/genericsOutlook
postemergenceAtrazineAccentCallisto2,4-DPermitAimglyphosate (RR corn)
Timing is critical!
Sicklepod Control in CornSicklepod Control in Corn
Conventional SystemsAtrazine2,4-DClarity
Herbicide-ResistantRR corn systemLL corn system
Nutsedge ControlNutsedge Control
not very competitive800 plants/100 row feet
only reduce yields by 2%
Eradicane or Sutan - PPIDual II Magnum or
generic – PRE Glyphosate – RR corn
Split applications
Basagran Permit
Tropical spiderwort (a.k.a. Benghal dayflower)Tropical spiderwort (a.k.a. Benghal dayflower)Commelina benghalensisCommelina benghalensis
tropical Africa native annual or perennial seeds and rhizomes above and below ground
flowers 1,600 seeds/plant alternate host of southern
root-knot nematode Reservoir for southern
stem blight (white mold)
TSW in GeorgiaTSW in Georgia
* confirmed in 29 counties by GA Dept. of Ag and UGA in 2004 (light blue)
* identified in 4 morecounties in 2005 (black)
*identified in 6 more counties in 2006 (dark blue)
TSW Control in Field CornTSW Control in Field CornDepends on planting
date2,4-D or Aim – POSTSequence or Expert in
RR cornAim/Gramoxone/Evik +
Dual Magnum – laybyPost-harvest may be
more important than in-cropTillage2 applications of 2,4-D,
Gramoxone, or Aim
Post-Harvest Control of Tropical SpiderwortPost-Harvest Control of Tropical Spiderwort
Untreated 2,4-D @ 1.5 pt/APOST1 + POST 2
($14.41/A)POST1: 8-10” tall COMBEPOST2: 2 weeks laterPhoto 1 week after POST2
Post-Harvest Control of Tropical Post-Harvest Control of Tropical SpiderwortSpiderwort
Untreated Gramoxone Inteon @ 1 qt/A + COC POST1 + POST2
($25.40/A)POST1: 8-10” tall COMBEPOST2: 2 weeks laterPhoto 1 week after POST2
Johnsongrass Control in CornJohnsongrass Control in Corn
Accent no OP soil insecticide hybrid tolerance to
Accent hybrid resistance to
MDMV
Glyphosate in RR corn
New Products Tested in 2006New Products Tested in 2006
Impact (toprazamene) Amvac POST Poor control of Texas panicum and sicklepod
Resolve (rimsulfuron) DuPont PRE and POST Crop Injury problems
Stout (Accent + Harmony GT) DuPont POST Crop Injury problems
Resolve 25WG (rimsulfuron) Injury to Field CornResolve 25WG (rimsulfuron) Injury to Field Corn 1.0 oz/A Applied PRE
Pictures @ 18 DAT
Stout Injury on Pioneer 3167 - 6 DATStout Injury on Pioneer 3167 - 6 DAT
CN-08B-06Attapulgus, GA
Future ProductsFuture Products
KIH-485 Kumiai similar activity to Dual
and Prowl but different structure and lower use rates
good on Palmer amaranth
Not yet been tested in Georgia
Texas Panicum Control in Field Corn in Texas
02040
6080
100
4 WAT 6 WAT 8 WAT
Time
Co
ntr
ol
- %
K- 0.22 lb ai/A DM - 0.95 lb ai/A
Source: Steele et al. 2005. WeedTechnology 19:866-869
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