ARS | Publication request: FLORIDA BEGGARWEED (DESMODIUM TORTUOSUM) AND SICKLEPOD (SENNA OBTUSIFOLIA) CONTROL IN PEANUT USING HERBICIDES APPLIED THROUGH A WICK-BAR.

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 26, 1999
Publication Date: N/A

Interpretive Summary: Weeds reduce peanut yields by competing for light, nutrients, and water. Most of the losses from weeds competing with peanut occur during the first half of the growing season. Removing weeds at mid- or late-season does not negate losses from earlier competition. However, removing tall weeds at mid-to late-season in peanut can improve fungicide deposition and harvest efficiency, indirectly improving peanut yields. Currently registered herbicides are inconsistent in controlling tall weeds in peanut at mid- to late-season. Therefore, studies were conducted at Archer, FL and Tifton, GA in 1994 and 1995 to determine the effectiveness of herbicides applied with a wick-bar for control of tall Florida beggarweed and sicklepod in peanut. Herbicides evaluated were glyphosate, paraquat, and endothall; each applied at 0, 25, 50, 75, and 100% by vol. Treatments were applied from 67 to 87 days after emergence, in two passes at opposite directions at tboth locations. Glyphosate and paraquat, at concentrations as low as 25% by vol., effectively controlled tall Florida beggarweed and sicklepod at both locations. Endothall did not adequately control Florida beggarweed or sicklepod at either location, regardless of rate. Peanut yields were not increased by weed control from any herbicide applied with a wick-bar. The only benefits from late-season Florida beggarweed control from herbicides applied with a wick-bar appear to be improved fungicide deposition and more efficient mechanical harvest, which is not consistently achievable with current herbicides.

Technical Abstract: Studies were conducted at Archer, FL and Tifton, GA in 1994 and 1995 to determine the effectiveness of herbicides applied with a wick-bar for control of tall Florida beggarweed and sicklepod in peanut. Herbicides evaluated were glyphosate, paraquat, and dimethyl alkyl amine salt of endothall (DMAA endothall); each applied at 0, 25, 50, 75, and 100% by vol. Each herbicide had a dedicated wick-bar to eliminate contamination among herbicides. Treatments were applied in two passes at opposite directions mid-season at both locations. Glyphosate and paraquat, at concentrations as low as 25% by vol., effectively controlled Florida beggarweed and sicklepod at both locations. DMAA endothall did not adequately control Florida beggarweed or sicklepod at either location, regardless of rate. Peanut yields were not increased by weed control from any herbicide applied with a wick-bar. The only benefits from late-season Florida beggarweed control with a wick-bar appear to be improved fungicide deposition and more efficient mechanical harvest.