What’s Happening in Weed Control 2001 Dr. Eric P. Prostko Extension Weed Specialist Tifton Certified Crop Advisors Meeting, Dec 15, 2000, Tifton GA

Topic for Discussion 2000 Problems peanuts cotton corn soybeans

How dry was it??? May Precipitation in Georgia 85-90% of GA peanuts were planted in May

Drift Problems in 2000 Staple Plus on Sorghum Roundup on Peanuts

Top 10 Tips For Reducing Pesticide Drift Problems nozzle selection reduce pressure lower boom height increase nozzle size avoid spraying when winds exceed 10 MPH lookout for inversions use additives calibrate sprayer keep records use common sense

“The Year of the Pigweed” dry weather incorporation big weeds Palmer amaranth resistance??

Palmer Amaranth Control with Blazer Applied at Different Timings Mayo et al. 1995 (KS)

Pigweed Control with Blazer and Classic - 28 DAT Gossett and Toler, 1999 (SC) Applied at V3-V4 stage

Pigweed Identification World Wide Web Iowa State University * http://www.weeds.iastate.edu/weed-id/ waterhemp/default.htm Kansas State University * http://www.oznet.ksu.edu/library/crpsl2/s80.pdf

PEANUTS

11% of peanut market in southeast - 2000

How would you rate the overall performance of Strongarm in your county? 2000 UGA County Agent Survey

What were the weeds that most frequently escaped control of Strongarm? 2000 UGA County Agent Survey

Strongarm - Does it work in GA? Attapulgus - 7 WAP Strongarm + Prowl (PPI) Untreated

Variety Tolerance to Strongarm (PRE) Tifton, GA 2000 Weed-free test Averaged over 2 varieties (GA Green, C99R) LSD 0.05 = 561

Strongarm How Should It Be Used in GA? use where starbur, eclipta, and copperleaf are problems tank-mix with DNA irrigate in if possible variable on nutsedge poor sicklepod control

Strongarm Label Update 2001 “at cracking” applications Snapbean rotation = 9 months

Valor 50WDG Valent introduced in 1989 flumioxazin N-phenylphthalimide derivative PPO oxidase inhibitor PRE 2-3 ozs/A label in 2001 (I hope!!)

Why do we need Valor?? Florida beggarweed rotation restrictions mode of action reduced costs/A?

Although Valor has many strengths, growers/dealers need to be made aware of its weaknesses such as . . . . cocklebur nutsedge sicklepod increased crop injury with delayed applications

Other Peanut Weed Control Issues paraquat formulations * Starfire (old) * Gramoxone Max * Boa Ultra Blazer * sodium salt vs. amine formulation * less peanut injury???

COTTON

GMO Cotton Varieties in GA Source: NASS, June 2000

Top 12 Varieties in 2000 GA Crop

Roundup Ready Programs

Glyphosate formulations (labeled for OT uses on RR cotton) * not Touchdown 5L

Glyphosate is a good herbicide but it does have some weaknesses such as ….. morningglory nutsedge dayflower hemp sesbania prickly sida Florida pusley

Say Bye Bye to Bladex (cyanazine) no sales or distribution after 9/30/02 cannot be used after 12/31/02 Does anyone have some??

Cyanazine Replacements Goal Harvade Valor glyphosate diuron prometryn fluometuron Cobra

Cyanazine Replacements Issues Contact activity (CoA) Residual activity (R) Carryover potential (CaP) Injury potential (I) Cost ($)

Cyanazine Replacements Strengths / Weaknesses diuron -- CoA, R, I, $ / CaP? prometryn -- CoA, R, CaP, I, $ fluometuron -- R, I, $ / CoA, CaP? Cobra -- CoA, CaP, I / R, $ Goal -- CoA, CaP, I / R, $ Harvade -- CoA, CaP, $ (IPOZZ) / R Valor -- CoA, R, CaP / I, $? experimental Glyphosate -- CoA, CaP, $ / R only RR

Conventional Programs

CORN

Weed Control in Corn numerous options tough to beat atrazine + cultivation ($$$) Prowl and/or Accent for PANTE need something for late-season MG

Weed Control in Corn New Stuff herbicide resistant hybrids * cost/A * hybrid performance * 6% of U.S. crop * GMO Issue new labels

Herbicide Resistant Corn Hybrid Technologies Cost/A

Herbicide Resistant Corn Hybrids in GA - 2000 hybrids that performed equal to or better than the test averages included the following: * Pioneer 32K63LL (Liberty) * Garst 8222 IT (Clearfield) * Dekalb 626RR (Roundup)

Weed Control in Corn New (er) Labels Accent Gold Action Axiom Axiom AT Aim Balance Celebrity Plus Distinct Degree Extra Epic Northstar Spirit

SOYBEANS

GA Soybean Production 1989-2000 Source: GASS

Weed Control in Soybeans Roundup Ready Tank-Mixes Classic @ 0.33 oz/A ($3.14) FirstRate @ 0.15 ozs/A ($3.11) Resource @ 4 ozs/A ($4.30) improved control of morningglory (5-10%) mixed results across southern US cheaper than split applications of Roundup but not as effective

Newer Roundup Premixes Soybeans BASF Extreme * Roundup (2 lb/gal) + Pursuit (0.17 lb/gal) Backdraft * Roundup (1.25 lb/gal) + Scepter (0.25 lb/gal) knockdown + residual NIS + N required on label

Roundup/Boron/Dimilin Tank Mixes?? full-bloom to early pod-fill R2-R3 stage Is this the best time for Roundup? Crop injury? Need more data

Soybean Yield Response to Roundup/Boron/Dimilin Tank-Mixes Hartz 7550RR Bu/A Tifton, GA 2000 P = 0.85 CV = 23

Weed Control in Soybeans Other New(er) Stuff Action Axiom Boundary Detail Domain Expert Pendimax Raptor Resource

http://mars.cropsoil.uga.edu/weedsci/ University of Georgia Extension Weed Science