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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #212699
Title: Weed control and phytotoxicity of delayed applications dinitroaniline herbicides in strip-tillage peanut production

Author
item Johnson, Wiley - Carroll
item PROSTKO, E - UNIV OF GA, TIFTON, GA

Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/12/2007
Publication Date: 12/15/2007
Citation: Johnson, W.C., Prostko, E.P. 2007. Weed control and phytotoxicity of delayed applications dinitroaniline herbicides in strip-tillage peanut production [abstract]. American Peanut Research and Education Society Abstracts. 39:80.

Interpretive Summary:

Technical Abstract: Situations occasionally arise where dinitroaniline herbicides are not applied in a timely manner to peanut; either preplant or immediately after seeding. This is particularly frequent in strip-tillage peanut production. In those cases, questions arise if dinitroaniline herbicides can be applied days or weeks after seeding. Trials were initiated in 2004 in Tifton, GA to determine the weed control efficacy of delayed applications of dinitroaniline herbicides and, in separate trials, the injury potential on peanut in strip-tillage peanut production. In the efficacy trials, treatments were a factorial arrangement of seven possible times of pendimethalin application and three possible tank-mixtures with pendimethalin. Pendimethalin was applied immediately after seeding, at vegetative emergence (VE) of peanut, 1-wk after VE, 2-wk after VE, 3-wk after VE, 4-wk after VE, and nontreated control. Tank mixtures with pendimethalin included paraquat, imazapic, and a nontreated control. Texas panicum was the predominant weed present both years. Pendimethalin alone did not control Texas panicum when applied after VE. Delayed applications of pendimethalin partially controlled Texas panicum when tank-mixed with either paraquat or imazapic, although the herbicide combinations applied at VE or 1-wk after VE provided superior Texas panicum control of all treatments evaluated. Separate weed-free studies evaluated the phytotoxicity of delayed applications of pendimethalin and ethalfluralin in strip-tillage peanut. Each herbicide was applied immediately after seeding, VE, 1-wk after VE, 2-wk after VE, 3-wk after VE, 4-wk after VE, and a nontreated control. Both herbicides temporarily stunted peanut when applied 2-wk and 3-wk after VE, based on visual estimates of injury. However, neither pod formation at mid-season nor final yield was affected by any treatment combination. These data show that in strip-tillage production systems, delayed applications of dinitroaniline herbicides are not overly injurious to peanut. However, Texas panicum control is reduced by delayed applications of pendimethalin and requires combinations with either paraquat or imazapic for acceptable weed control.