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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #134986
Title: ANNOYING TRENDS IN STRIP-TILLAGE WEED CONTROL IN PEANUT - WHAT ARE OUR OPTIONS?

Author
item Johnson, Wiley - Carroll
item PROSTKO, E - UNIVERSITY OF GEORGIA
item GREY, T - UNIVERSITY OF GEORGIA

Submitted to: Annual Southern Conservation Tillage Conference for Sustainable Agriculture
Publication Type: Proceedings
Publication Acceptance Date: 5/27/2002
Publication Date: 6/24/2002
Citation: Johnson, W.C., Prostko, E.P., Grey, T.L. 2002. Annoying trends in strip-tillage weed control in peanut - what are our options? In: van Santen, E. (ed.). Making Conservation Tillage Conventional: Building a Future on 25 Years of Research. Proceedings of the 25th Annual Southern Conservation Tillage Conference for Sustainable Agriculture, Auburn University, AL. 25:165-170.

Interpretive Summary: Growers in the southeastern U. S. are rapidly adapting conservation tillage practices, with strip-tillage being the most common form of conservation tillage. One of the troublesome challenges of strip-tillage peanut production is Texas panicum control. Texas panicum is one of the most common weeds of peanut in the southeastern U. S., very competitive, and difficult to control. Studies were conducted from 1999 to 2001 in Georgia to develop Texas panicum management systems in strip-tillage peanut production into a killed rye cover crop. Preemergence (PRE) herbicides were evaluated for Texas panicum control; Sonalan®, Prowl®, Dual®, Lasso®, Frontier®, and a nontreated PRE control. All plots were irrigated immediately after PRE applications to activate herbicides. These trials also included postemergence (POST) graminicides applied 28 days after peanut emergence; Poast®, Select®, and a nontreated POST control. None of the PRE herbicides alone adequately controlled Texas panicum in strip-till peanut production, even with optimum activation with irrigation. Both sethoxydim and clethodim consistently controlled Texas panicum, regardless of PRE treatments. While POST graminicides effectively controlled Texas panicum in strip-till peanut production, their use to the exclusion of PRE herbicides could leave small-seeded dicot weeds uncontrolled. Growers who choose to use irrigated strip-till peanut production must plan to use a properly timed POST graminicide for Texas panicum control in addition to traditional dinitroaniline herbicides. Peanut growers need to be mindful of this additional cost when making decisions on tillage systems and it needs to be factored into peanut production budgets.

Technical Abstract: Controlling Texas panicum in peanut has been troublesome to growers attempting to implement strip-tillage production practices. Studies were conducted from 1999 to 2001 in Georgia to develop Texas panicum management systems in strip-tillage peanut production. The experimental design was a split-plot with four replications. Main plots were preemergence (PRE) herbicides for annual grass control; ethalfluralin (0.8 kg ai/ha), pendimethalin (1.1 kg ai/ha), metolachlor (2.2 kg ai/ha), alachlor (3.4 kg ai/ha), dimethenamid (1.3 kg ai/ha), and a nontreated PRE control. All plots were irrigated immediately after PRE applications to activate herbicides. Sub-plots were postemergence (POST) graminicides applied 28 days after peanut emergence; sethoxydim (0.22 kg ai/ha), clethodim (0.10 kg ai/ha), and a nontreated POST control. POST graminicides were applied with a crop oil concentrate at 1.0% by vol. None of the PRE herbicides alone adequately controlled Texas panicum in strip-till peanut production, even with optimum activation with irrigation. Both sethoxydim and clethodim consistently controlled Texas panicum, regardless of PRE treatments. While POST graminicides effectively controlled Texas panicum in strip-till peanut production, their use to the exclusion of PRE herbicides could leave small-seeded dicot weeds uncontrolled. Growers who choose to use irrigated strip-till peanut production must plan to use a properly timed POST graminicide for Texas panicum control in addition to traditional dinitroaniline herbicides. This additional cost needs to be factored into crop production budgets.