"Soil Applied Residual Herbicide Affect on Conventional and Imidazolinone Resistant Canola in the Southeastern US Timothy Grey1"
Soil Applied Residual Herbicide Affect on Conventional and Imidazolinone Resistant Canola in the Southeastern US Timothy Grey1, Paul Raymer2, and G. David Buntin2 1The University of Georgia, 115 Coastal Way, Tifton, Georgia, 31793-0748, firstname.lastname@example.org, 21109 Experiment St. Griffin Georgia 30223 INTRODUCTION Table 1. Herbicide treatments for canola herbicide resistance study. Interest in canola quality oilseed rape, Brassica naupus L., in the southeastern US has recently increased (Anonymous 2002) . There are several potential markets for canola in this region including: Injury Stand counts Treatment Rate Pioneer 45A71 Flint Pioneer 45A71 Flint 1) whole grain exports of non-genetically modified canola, 2) newly developed specialty oil lines, 3) _ g ai/ha_ ____________ _____________ % ________ plants/m row_________ RESULTS AND DISCUSSION improved commodity prices (ERS-USDA 2002) and 4) production uses for biodiesel. Agronomic 1 Nontreated 0 0 0 26 32 production of a profitable canola crop in the southeastern U.S. will depend on reliable information Pioneer 45A71 and Flint canola exhibited extensive injury and about rotational restrictions to cotton, peanut, and other agronomic herbicides. Agronomic row crop 2 Diclosulam 20 21 99 23 1 nearly complete stand failure (Table 1) and crop loss with the PPO production in Georgia, Florida, Alabama, and South Carolina represent 1,005,000 hectares of cotton, herbicides flumioxazin, fomesafen, and sulfentrazone (Figure 4). This 323,300 hectares of corn, 329,820 hectares of peanut, 348,030 hectares of soybean, and 25,500 3 Diclosulam 41 43 100 17 0 susceptibility resulted in in no or significantly reduced yields (data not hectares of tobacco (NASS, 2002). Wheat, oats, and rye, planted in winter rotations with these crops 4 Diclosulam 82 63 100 14 0 shown). For the ALS herbicides imazapic, chlorimuron, pyrithiobac, represent 434,230 hectares (NASS, 2002). Canola integrated as part of a winter rotation, October and trifloxysulfuron, Pioneer 45A71 canola injury was 17% or less for planted and May harvested, could potentially increase farmer profits, as an alternative oil seed crop. 5 Imazapic 18 1 96 26 3 all rates (Figure 5) and yields were not different from the nontreated Herbicides used in row crop production in the southeastern U.S. vary by crop. In the south, control (Data not shown). Pioneer 45A71 exhibited excellent tolerance 6 Imazapic 35 1 97 24 1 imazapic and diclosulam are applied to approximately 85% of the peanut hectares. Pyrithiobac is to imazapic at ¼, ½, and 1x rates (Figure 2). In contrast, Flint canola applied to greater than 30% of the cotton crop. Imazapic, diclosulam, and pyrithiobac mode of action 7 Imazapic 71 6 100 18 1 exhibited 57% injury or greater (Figures 3 & 5) and yield reductions for is through acetolactate synthase (ALS) inhibition. Other ALS herbicides used in these crops include imazapic, chlorimuron, pyrithiobac, diclosulam, and trifloxysulfuron at chlorimuron and trifloxysulfuron. Herbicides having different modes of action that are used in the 8 Chlorimuron 2 12 57 27 20 all rates (Data not shown). southeastern US in cotton and peanut include sulfentrazone, fomesafen, and flumioxazin. However, 9 Chlorimuron 4 4 71 23 19 Pioneer 45A71 exhibited dose response injury of 21, 43, and 63% rotational data for these herbicides for canola have not been established in the southeastern U.S. for the ¼, ½, and 1x rates of diclosulam, respectively (Figure 5). One reason to evaluate canola for herbicide carryover in this region is the moderate temperature and 10 Chlorimuron 9 13 83 27 13 Additionally, stand was reduced from 26 to 14 plants/m row for the moisture regimes that can perpetuate the degradation of pesticides. nontreated check to diclosulam at 82 g/ha, respectively. This indicates 11 Pyrithiobac 13 10 68 23 26 Clearfield canola cultivars have ALS resistance, specifically to imidazolinone herbicides. that imi-resistant canola is not resistant to all ALS herbicides which Clearfield-resistant canola was marketed commercially in Canada during 1998 and is now available for 12 Pyrithiobac 27 9 81 27 19 should be considered when planning potential rotational options for evaluation in the United States. The use of Clearfield canola could be very beneficial for canola canola. growers in the southeastern U.S., allowing the use of imazamox herbicide that has selective control of 13 Pyrithiobac 54 17 93 24 15 wild radish (Raphanus raphanistrum L.), many other dicot weeds, and Italian ryegrass (Lolium 14 Trifloxysulfuron 5 8 68 22 21 multiflorum Lam.) (Grey et al. 2003). Additionally, Clearfield canola potentially could be grown with reduced risk of injury, in rotation with cotton, peanuts, and other row crops that have had ALS mode 15 Trifloxysulfuron 8 5 69 26 21 of action herbicides (imazapic, diclosulam, pyrithiobac, etc.) applied for weed control. However, Figure 4. PPO inhibitor injury on Pioneer 45A71 and Flint canola. 16 Trifloxysulfuron 13 15 81 28 16 research for tolerance to these herbicide has not been established. 100 17 Flumioxazin 26 79 79 12 9 90 MATERIALS & METHODS 80 Experiments were conducted in Georgia during 2002-2003 at the Bledsoe Research Farm near 18 Flumioxazin 53 88 91 8 5 70 Williamson and in 2003-2004 and 2004-2005 at the Southwest Georgia Branch Experiment Station % injury 19 Flumioxazin 108 98 98 1 3 60 Herbicide rate located near Plains in separate areas of the same field. Soils were a Cecil sandy clay loam (clayey, 50 kaolinitic, thermic, Typic Hapludult) at Williamson and a Faceville sandy loam (clayey, kaolinitic, 20 Fomesafen 105 68 80 19 21 1/4 x 40 1/2 x thermic, Typic Kandiudults) at Plains. Organic matter ranged from 1.0 to 2.0% with pH from 6.0 to 6.5 30 21 Fomesafen 210 82 87 10 8 1x at both locations. In the fall of each season, seedbeds were conventionally tilled using a moldboard 20 plow and smoothing with a rotary tiller. Canola was seeded with a Great Plains drill with a 19 cm row 22 Fomesafen 420 97 90 4 1 10 width on October 11, 2002, November 11, 2003, and October 18, 2004 at a rate of 28 seed per m of row. 0 Each experiment was arranged as a split plot with treatments replicated four times. Plot size was 3.66 23 Sulfentrazone 105 84 85 13 14 nt t nt 1 71 71 li n A7 Fli m wide by 7.6 m long (Figure 1). Herbicides were PRE applied with a CO2-pressurized backpack Fli 5A 5A nF 45 24 Sulfentrazone 210 85 84 7 13 in P4 e P4 sprayer calibrated to deliver 187 L/ha at 210 kPa. Emergence dates for all trials was approximately nP fe on az sa in e az ox one week after planting. Split plots were seeded on 1.83 m bed with imidazolinone-tolerant ‘Pioneer fe on az me 25 Sulfentrazone 280 93 89 7 12 ntr sa mi az ox 45A71’ and on the other 1.83 m bed to the to conventional canola ‘Flint’. The intent was to determine Fo me l fe Flu ntr mi Su Fo l fe Flu tolerance to ALS herbicides. Su Screening of herbicide tolerance to two classes of herbicides was investigated. Modes of action Herbicide/canola combination included acetolactate synthase inhibitors (ALS) and protoporphyrinogen oxidase inhibitors (PPO). Imazapic rate Five ALS herbicides and three PPO herbicides were evaluated. Factors included cultivars (IMI- tolerant canola and traditional canola) and herbicide rate (1x, ½x, ¼x) that resulted in 25 treatments. Figure 2 (Left). Imazapic carryover Treatments included a nontreated check, the ALS herbicides diclosulam, imazapic, chloriuron, simulation to Pioneer 45A71 (left bed of each ¼X pyrithiobac and trifloxysulfuron, and the PPO herbicides flumioxazin, fomesafen, and sulfentrazone. picture) and Flint (right bed of each picture) at (Table 1). ¼ x (top), ½ x (middle), and 1x rates (bottom). Figure 5. ALS inhibitor injury on Pioneer 45A71 and Flint canola. Crop injury was visually estimated on a scale of 0 (no injury) to 100% (death). Crop injury ratings Note dose response for Flint from ¼x to ½x were taken at 140, 70, and 58 days after planting (DAP) for the 2002, 2003, and 2004 plantings, rates but no difference for Pioneer 45A71. 100 respectively. Canola stand counts were taken 58 DAP for the 2004 planting. Plots were harvested 90 (2004 only) with conventional plot combine. 80 70 % injury REFERENCES 60 Anonymous. 2002. Oilseed plant going to Claxton in Georgia Faces. Univ. Georgia College of Agric. & Env. Sci. at 50 Herbicide rate http://georgiafaces.caes.uga.edu 40 1/4 x Economic Research Service - U.S. Department of Agriculture (ERS-USDA). 2002. Title I, Commodity Programs in Farm 30 1/2 x Policy, the 2002 farm bill: provisions and economic implications. at http://www.ers.usda.gov/Features/farmbill/ ½X 1x 20 National Agricultural Statistics Service (NASS). 2002. National Agricultural Statistics Service U.S. Dept. of Agri.. 2000 10 Annual summary. NASS-USDA, Washington, DC. 0 Figure 1. Pioneer 45A71 (staked bed, left) and Flint (nonstaked bed, right) canola planted in Plains, GA. nt nt 1 nt 1 t 71 1 l in 7 7 A7 Fli Fli Fli 5A 5A 5A Figure 3 (Top). Imazapic carryover nF 45 pi c lam n P4 P4 P4 uro ro nP simulation to Flint canola from ¼x za pi c lam n u lfu uro im los ro a application rate. su za Im u lfu l or Dic im los a xy su Im Ch l or flo Dic xy Ch Tri flo Tri 1X Herbicide/canola combination