2012: Changes in Cotton Weed M anagement Practices in Georgia Following the Development of Glyphosate-Resistant Palmer Amaranth Lynn M . Sosnoskie 1,2 and A. Stanley Culpepper 1 1 University of Georgia - Tifton 2 University of California - Davis
Distribution of GR Palmer amaranth Map credit: R. L. Nichols
Cotton producing regions in US Map credit: http://www.cottonusa.org/
Glyphosate-resistant cotton: Changes in weed management • Shaner (2000) Pest M anage. Sci. 56:320-326. – Glyphosate use increasing in cotton – Concomitant decrease in: • PS II inhibitors – diuron, fluometuron, prometryn • DNAs – pendimethalin, trifluralin • Arsenates – M SM A • Carotenoid biosynthesis inhibitors - clomazone
Glyphosate-resistant cotton: Changes in weed management • Young (2006) Weed Technol. 20:301-307. – Increase in glyphosate applications: • 1/ crop (1996) to 1.8/ crop (2001) – Decreased use of fluometuron and trifluralin: • Fluometuron - 27-44% (1992-1998) to 20-27% (1999-2001) • Trifluralin – 52-67% (1992-1999) to 30-39% (2000-2001) • Glyphosate – 30-36% (1998-1999) to 56-57% (2000-2001)
Objective: To determine if cotton weed management practices in Georgia have changed following the development of glyphosate-resistant Palmer amaranth
Survey development and administration • Two surveys (growers and extension agents) • Surveys were designed by the authors and reviewed by an expert committee consisting of: extension agents, University (UGA and other) research scientists, UGA rural sociologist, industry personnel • Surveys were ‘identical’ except for the fact that the growers were asked (anonymously) about their individual farming practices and agents provided 3 rd party information about county-wide activities
Survey development and administration • Final survey was 8 pages long, contained 19 questions, and was administered in person • Survey sections: – Commodities/ acreage BEFORE – Herbicide use 2000-2005 – Additional weed management practices • Tillage, cultivation, hand-weeding AFTER – Weed problems 2006-2010 • Including the presence and severity of glyphosate-resistant Palmer amaranth
Survey development and administration • E-mail was sent to all Georgia extension agents with cotton responsibilities (2010) describing the survey and requesting that they and 3-5 ‘representative’ growers in their county participate in the process • Grower qualifications: – Cotton production – Responsible for making (agricultural) decisions on their property – Did not work for a chemical manufacturer, distributor, of retailer, nor a seed company
County Data 2009 Georgia Farm Gate Value Report (AR-10-01) County * Cotton acres Value (M illions) Cotton rank Total commodity rank Berrien 21,804 $14.3 18 41 Candler 9,000 $6.5 35 79 Grady 22,403 $17.0 14 16 Irwin 28,269 $20.5 10 43 M acon 9,781 $6.4 36 11 M iller 28,366 $21.6 8 47 Randolph 7,229 $6.0 40 73 Seminole 24,369 $14.1 20 56 Screven 12,822 $12.1 24 62 Sumter 17,697 $11.5 25 26 Taylor 452 $0.2 77 88 Terrell 15,466 $9.5 16 75 Tift 18,820 $12.2 23 19 Thomas 25,858 $17.3 13 37 Turner 20,879 $15.1 16 54 Worth 49,185 $37.8 4 21 * Extension agent from Colquitt County also returned a survey (54,010 acres, $42.1 M illion, Rank = 2).
Total grower (n = 65) acres = 129,615 (12.6% of GA cotton) Total agent county (n = 10) acres = 246,034 (24% of GA cotton)
Commodities - example Grower Question 4: How many acres do you farm?____________________ Grower Question 5: What types of agricultural commodity groups do you produce on your farm? Yes No Approximate number of acres or number of heads, houses or ponds Row and forage crops ___ ___ _____________________ Poultry and eggs ___ ___ _____________________ Livestock and aquaculture ___ ___ _____________________ Forestry products ___ ___ _____________________ Vegetables ___ ___ _____________________ Ornamental horticulture ___ ___ _____________________ Other (Please describe) (Continued on next page)
Commodity composition of growers' farms 120.0 100.0 100.0 Percent (%) of surveyed growers 80.0 60.0 36.9 35.4 40.0 18.5 20.0 3.1 3.1 3.1 0.0 Row and forage Poultry and Livestock and Forestry Vegetables Ornamentals Other eggs aquaculture and turf
Herbicides - example Grower Question 9: What herbicides have you relied on for weed control in cotton before (2000- 2005) and after (2006-2010) the development of glyphosate-resistant Palmer amaranth (pigweed)? On what percent of you row crop acreage have you used each product? PREPLANT and PREEMERGENCE (burndown (including early), applications made at or prior to planting, and applications made prior to cotton emergence): Before (2000-2005): After (2006-2010): Yes No Average % of Acres Yes No Average % of Acres Roundup, Glyphomax, Touchdown, others ___ ___ _________________ ___ ___ _________________ 2,4-D ___ ___ _________________ ___ ___ _________________ Aim ___ ___ _________________ ___ ___ _________________ Clarity ___ ___ _________________ ___ ___ _________________ Valor SX ___ ___ _________________ ___ ___ _________________ Direx, others ___ ___ _________________ ___ ___ _________________ Firestorm, Parazone, Gramoxone Inteon ___ ___ _________________ ___ ___ _________________ (Continued on next page)
Herbicides - example Herbicides are not divided up/grouped by MOA, activity, selectivity Grouped by timing of application as expressed in Georgia Pest Management handbook (http://www.ent.uga.edu/pmh/). 1. PREPLANT and PREEMERGENCE (burndown (including early), applications made at or prior to planting, and applications made prior to cotton emergence): 2. POSTEMERGENCE OVER-THE-TOP (following cotton emergence): 3. POSTEMERGENCE DIRECTED:
Growers: Pre-plant herbicides applied Percent (%) of acres treated 100 86.1 90 * Percent (%) of acres treated 80 73.7 70 60 50 * * 38.6 40 34.2 29.4 24.7 30 14.9 20 10 0.5 0 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 Glyphosate 2,4-D Paraquat Glufosinate
Agents: Pre-plant herbicides applied Percent (%) of acres treated 100 87.5 90 74.3 Percent (%) of acres treated 80 * 70 58.9 60 * 50 37.5 40 30 23 23.3 * 20 11.8 10 0.3 0 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 Glyphosate 2,4-D Paraquat Glufosinate
Growers: Pre-plant* / PRE herbicides applied Percent (%) of acres treated 100 * 90 81 80 Percent (%) of acres treated 70 * 60 45.8 50 * 37.8 40 26.9 25.1 26.9 24.7 30 15.1 20 8.1 10 2.8 0 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 Diuron Fluometuron Pyrithiobac Flumioxazin Fomesafen *
Agents: Pre-plant* / PRE herbicides applied Percent (%) of acres treated 100 90 80 Percent (%) of acres treated * 70 58 60 50 * * 40 25.5 29.1 30 20 11.7 11.2 11.2 8.1 6.7 10 3.4 2.7 0 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 Diuron Fluometuron Pyrithiobac Flumioxazin Fomesafen *
PPI herbicides applied Percent (%) of acres treated 100 90 Percent (%) of acres treated * 75.9 80 69.9 68.5 70 60 50 37 40 29.6 25.2 30 16.9 20 11 10 0 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 Pendimethalin Trifluralin Pendimethalin Trifluralin Growers Agents GROWERS AGENTS
Growers: POST herbicides applied Percent (%) of acres treated * 100 94.4 88.4 90 80 Percent (%) of acres treated * 70 54.4 60 45.7 50 * 40.8 40 29.7 30 16.3 20 10 0.6 0 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 Glyphosate Glufosinate Pyrithiobac S-metolachlor
Agents: POST herbicides applied Percent (%) of acres treated 100 95 90 * 80 Percent (%) of acres treated 74.7 70 60 * 50 42 * 40.3 38.3 40 33.5 30 20 11.9 10 0.5 0 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 2000-2005 2006-2010 Glyphosate Glufosinate Pyrithiobac S-metolachlor
Growers: PD herbicides applied Percent (%) of acres treated 100 90 d e 80 t a 67.9 e r 70 63.3 t 61.6 60 s 59.3 * e 60 r c 46.3 a f 50 o ) % 40 ( * * t n 25.5 30 e 23.1 c r e 20 P 9.6 10 0 0 2 2 2 2 2 2 2 2 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 0 6 0 6 0 6 0 6 - - - - - - - - - - 2 2 2 2 2 2 2 2 2 2 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 0 1 0 1 5 0 5 0 5 0 5 0 5 0 Glyphosate MSMA Diuron Flumioxazin S-metolachlor
Agents: PD herbicides applied Percent (%) of acres treated 100 90 * * d e 80 74 t a 68.5 70 e r 70 t s e 60 r c * a f 50 o 41 40 * ) % 40 34 ( t 29.5 n 30 e c * r e 20 P 9.2 5.4 10 3.5 0 2 2 2 2 2 2 2 2 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 0 6 0 6 0 6 0 6 - - - - - - - - - - 2 2 2 2 2 2 2 2 2 2 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 1 0 1 0 1 5 0 5 0 5 0 5 0 5 0 Glyphosate MSMA Diuron Flumioxazin S -metolachlor
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