Use of Fenoxaprop-p-ethyl and Lactofen in Soybean Grown after Rice

Abstract

Two field trials were conducted during December 1992 to May 1993 in farmer's field, Chiang Mai Province. Herbicides were applied as postemergence to soybean grown after rice at 17 and 24 days after planting with knapsack sprayer in the spray volume of 500 l/ha. Fenoxaprop-p-ethyl ((±)-2- [4[(6-chloro-2-benzoxazolyloxy)]phenoxy]-propanoic acid) alone at 56.25 g (ai)/ha gave excellent control of annual grass weeds; Digitaria adscendens, Eleusine indica, Echinochloa crus-galli, Dactyloctenium aegyptium when applied at 17 days after planting. Use of fenoxaprop-p-ethyl for annual grass weed control in soybean did not toxic to the crop and were able to increase yield up to 13% compared to non treated plot. The selective-broadleaf herbicide lactofen ((±)-2-ethoxy 1-methyl-2-oxyethyl-5-[2-chloro-4-(trifluormethyl)phenoxy]-2-nitrobenzoate) applied alone at the rate of 90-120 g (ai)/ha provided excellent control of annual broadleaf weeds; Physalis minima, Ageratum conyzoides, Eclipta alba, Amaranthus spinosus. However, the application of lactofen caused phytotoxicity to soybean. The tank mixes of lactofen and fenoxaprop-p-ethyl decreased the efficacy of fenoxaprop-p-ethyl in controlling annual grass weeds The use of fenoxaprop-p-ethyl mixed with lactofen could not increased yield of soybean.