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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #211386
Title: Weed control as affected by pendimethalin timing and application method in conservation tillage cotton (Gossypium hirsutum L.)

Author
item GREY, T - UNIV OF GA, TIFTON,GA
item Webster, Theodore
item CULPEPPER, A - UNIV OF GA, TIFTON,GA

Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2008
Publication Date: 10/31/2008
Citation: Grey, T.L., Webster, T.M., Culpepper, A.S. 2008. Weed control as affected by pendimethalin timing and application method in conservation tillage cotton (Gossypium hirsutum L.). J. Cotton Science. 12:318-324.

Interpretive Summary: Cotton production in the southeastern United States exceeds 831,000 hectares, with an estimated annual farm gate value of $700 million. Since commercial introduction in 1997, glyphosate resistant cotton has readily been accepted by growers. The technology has allowed growers to reduce or eliminate soil-applied herbicides and to abandon cultivation. It also has allowed a shift to conservation tillage; approximately 50% of Georgia cotton production, with herbicides as the primary method used for weed control. An alternative method to spraying pendimethalin is to impregnate on fertilizer prior to application, which saves time and labor, reduces soil compaction by eliminating field operations, and reduces applications costs. Field studies were conducted in conservation tillage cotton to evaluate control of Texas panicum and Florida pusley with pendimethalin applied as either a spray application or when impregnated onto fertilizer in conservation tillage cotton. Texas panicum and Florida pusley control were similar and not reduced when pendimethalin was impregnated on fertilizer as compared to pendimethalin applied through a spray solution. This research indicates that the time of pendimethalin application was critical for Florida pusley control with PRE application providing greater control than eight or four-week-before-planting treatments. There were no indications that rate of pendimethalin applied or, method of application (spray or fertilizer impregnated), were different.

Technical Abstract: Field studies were conducted in 2004, 2005, and 2006 to evaluate weed control with pendimethalin preemergence (PRE) applied in conservation tillage cotton. Pendimethalin was applied at eight weeks, four weeks, or on the day of planting either as an aqueous solution (sprayed) or impregnated on fertilizer. Texas panicum and Florida pusley control were similar and not reduced when pendimethalin was impregnated on fertilizer as compared to pendimethalin spray applied with 140 L/ha at four weeks PRE, or PRE on the day of planting. Control of Florida pusley (25 to 88%) and Texas panicum (39 to 83%) were variable when pendimethalin was applied four or eight weeks prior to cotton planting, regardless of method of application. Pendimethalin at 1.1 or 1.7 kg ai/ha impregnated on 280 or 560 kg/ha fertilizer either four wks PRE to planting, or PRE applied on the day of planting, did not negatively affect weed control. Control of Texas panicum (71 to 95%) and Florida pusley (68 to 94%) at four wks after planting was achieved with a split spray application of pendimethalin at 0.84 kg/ha at four wks PRE followed by the same treatment on the day of planting PRE. Similar control was observed when pendimethalin at 0.84 kg/ha was impregnated on 280 or 560 kg/ha fertilizer four wks PRE then followed by a spray application of pendimethalin at 0.84 kg/ha applied on the day of planting PRE.