Postemergence Jimsonweed (Datura stramonium) Control as Influenced by Soil-Applied Vernolate and Trifluralin

Abstract

Under greenhouse conditions, jimsonweed (Datura stramonium) L. ♯3DATST) grown in soil treated with vernolate (S-propyl dipropylthiocarbamate) was more sensitive to postemerence application of acifluorfen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid} and bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] than jimsonweed grown in untreated soil or soil treated with trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine). Vernolate followed by acifluorfen was more phytotoxic than acifluorfen alone. Bentazon applied to jimsonweed after a pretreatment with vernolate at 2.2 kg ai/ha was more effective than the same rate of bentazon applied alone. Trifluralin did not enhance the activity of acifluorfen or bentazon on jimsonweed. Laboratory studies showed that more acifluorfen was absorbed by vernolate-pretreated jimsonweed than by untreated jimsonweed. No differences in bentazon absorption between vernolate-pretreated and nontreated jimsonweed were measured.