Weed Control in ‘Concord’ Grapes in Arkansas1

Abstract

Abstract Midsummer grapehoeing following spring application of diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] or simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] plus paraquat (1,1’-dimethyl-4,4’-bipyridinium ion) adequately controlled weeds growing in grapes (Vitis labrusca L.). When grapehoeing was used to control grape root borer [(Vitacea polistiformis Harris) lower initial rates of preemergence herbicide could be used. An additional half-rate of herbicide was required after grapehoeing to maintain weed control through the fall. Plots not grapehoed were almost completely weed free following a glyphosate [N-(phosphonomethyl)glycine] treatment. Injury to grapes the following spring was associated with fall glyphosate applications where low hanging foliage, that had not been removed, intercepted the spray. Glyphosate was most effective and paraquat more effective than dinoseb (2-sec-buty1-4,6-dinitrophenol) plus diesel fuel for postemergence control of weeds in grapes. Preemergence herbicides, napropamide [2-(α-naphthoxy)-N,N-diethylpropionamide], norflurazon [4-chloro-5-(methylamino)-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone], oxadiazon [2-tert-buty1-4-(2,4-dichloro-5-isopropoxyphenyl)-∆2-l,3,4-oxadiazolin-5-one], oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide), and oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene], were effective as residual type treatments.