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United States Department of Agriculture

Agricultural Research Service

Research Project: INTEGRATED MANAGEMENT AND ECOLOGY OF WEED POPULATIONS IN THE SOUTHEASTERN COASTAL PLAIN Title: Phytotoxicity of Delayed Applications of Dinitroaniline Herbicides in Strip-Tillage Peanut Production

Authors
item Johnson, Wiley
item Prostko, E.P. -
item Davis, Jerry -

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 1, 2011
Publication Date: March 17, 2011
Citation: Johnson, W.C., Prostko, E., Davis, J. 2011. Phytotoxicity of Delayed Applications of Dinitroaniline Herbicides in Strip-Tillage Peanut Production. Peanut Science. 38:57-60.

Interpretive Summary: Ethalfluralin and pendimethalin are typically applied before or immediately after planting peanut. Situations frequently arise where these herbicides are not applied in a timely manner, particularly in strip-tillage production systems. In these cases, herbicides are be applied several days or weeks after seeding peanut. Weed-free, irrigated field trials were conducted in Tifton, GA in 2004 and 2005 to evaluate the phytotoxic effects of delayed applications of ethalfluralin and pendimethalin on peanut. Each herbicide was applied immediately after planting (PRE), at vegetative emergence (VE), 1wk after vegetative emergence (VE+1wk), VE+2wk, VE+3wk, VE+4wk, and a nontreated control. Dinitroaniline herbicides did not visually injure peanut and affect foliage biomass collected at mid- and late-season. Times of herbicide application did not consistently affect measurements of peanut vegetative growth. Pod biomass was reduced by dinitroaniline herbicides applied VE+3wk when measured mid-season, but recovered late-season. Across all times of application, ethalfluralin reduced peanut yield compared to pendimethalin. Across both dinitroaniline herbicides, peanut yields were reduced when herbicides were applied at VE. These data show that visual estimates of peanut response to dinitroaniline herbicides do not detect subtle phytotoxic effects. The data also suggests that pod biomass and yield effects may be difficult to predict. However, there is potential for significant injury if peanut are treated with delayed applications of dinitroaniline herbicides in strip-tillage peanut production. In contrast, PRE applications are not injurious to strip-tillage peanut and must be a priority to ensure crop safety.

Technical Abstract: Dinitroaniline herbicides are typically applied preplant incorporated or preemergence (PRE) immediately after seeding peanut. Situations frequently arise where dinitroaniline herbicides are not applied in a timely manner in strip-tillage peanut production. In these cases, dinitroaniline herbicides are be applied several days or weeks after seeding peanut. Weed-free, irrigated field trials were conducted in Tifton, GA in 2004 and 2005 to evaluate the phytotoxic effects of delayed applications of ethalfluralin and pendimethalin on peanut. Herbicides were applied PRE, at vegetative emergence (VE), 1wk after vegetative emergence (VE+1wk), VE+2wk, VE+3wk, VE+4wk, and a nontreated control. Dinitroaniline herbicides did not visually injure peanut and affect foliage biomass collected at mid- and late-season. Times of herbicide application did not consistently affect measurements of peanut vegetative growth. Pod biomass was reduced by dinitroaniline herbicides applied VE+3wk when measured mid-season, but recovered late-season. Across all times of application, ethalfluralin reduced peanut yield compared to pendimethalin. Across both dinitroaniline herbicides, peanut yields were reduced when herbicides were applied at VE. These data show that visual estimates of peanut response to dinitroaniline herbicides may not detect subtle phytotoxic effects. The data also suggests that pod biomass and yield effects may be difficult to predict. However, there is potential for significant injury if peanut are treated with delayed applications of dinitroaniline herbicides in strip-tillage peanut production. In contrast, PRE applications are not injurious to strip-tillage peanut and must be a priority to ensure crop safety.

Last Modified: 12/21/2014
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