Evaluation of Runner-Type Peanut Cultivar Tolerance to Paraquat Tank Mixes

Abstract

Herbicide tank mixes are often used to reduce peanut injury caused by paraquat and broaden the weed control spectrum. New peanut cultivars are continuously being introduced therefore determining tolerance to paraquat based herbicide programs is essential to provide growers with appropriate recommendations. The objective of this trial was to evaluate effect of paraquat based herbicide programs on newer peanut cultivars growth and yield. Field trials were conducted in Macon, Henry and Baldwin counties in Alabama in 2016 and 2017 and the peanut cultivars ‘Georgia 06G', ‘Georgia 12Y', ‘Georgia 14N', and ‘TufRunner 511’ were evaluated. Paraquat was applied alone (210, 280, 420 g ai/ha), in tank mixes with either bentazon plus acifluorfen or 2,4-DB and one of the following, S-metolachlor, pyroxasulfone, acetochlor, or pyroxasulfone plus carfentrazone at the highest labeled rates 3 to 4 wk after peanut planting. No cultivar by treatment interactions were observed for any growth parameters evaluated for any location. In 2017, paraquat either applied at 280 g ai/ha alone, tank mixed with S-metolachlor plus 2,4-DB, or with S-metolachlor plus bentazon plus acifluorfen significantly reduced canopy widths of 22 to 30%, 12 to 22%, and 20 to 37% respectively at 45 to 48 DAP when compared to the non-treated check (NTC). Yield reductions compared to the NTC were rare, paraquat plus bentazon plus acifluorfen plus pyroxasulfone plus carfentrazone had a 13% yield loss in Henry County and a 7% yield loss with paraquat 280 g ai/ha at Baldwin County in 2016 only. Data indicates peanut stunting may be observed following applications of paraquat tank mixes evaluated in this study, but it is unlikely these effects result in yield loss.