Preliminar evaluation of imazaquin for weed control in soybeans under "cerrado"

Abstract

The effects of imazaquin {3-quinolinecarboxylic acid, 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl}, acifluorfen {5-(2-chloro-4-(trifluoromethyl) fenoxy)-2-nitrobenzoic acid}, fomesafen {5-(2-chloro-4-(trifluoromethyl) phenoxy)-N-methylsulfonyl-2-nitrobenzamide}, bentazon {3-isopropyl-1 H-2,1 ,3-benzothiadiazin-4 (3H)-one 2,2 dioxide}, metribuzin {4-amino tert-butyl-3-(methylthio)-as-triazin-5 (4H)-one} and alachlor {2-chloro-2',6'-dietyl-N-(methoxymethyl) acetanilide} upon soybeans [Glycine max (L.) Merr.] weed control were evaluated. The post-emergence application of imazaquin at 0.25 kg/ha showed slight initial phytotoxicity to the crop, without affecting crop grain yield. Fomesafen and acifluorfen also showed phytotoxicities although less injurious than imazaquin. It was also observed that the preemergence applications of imazaquin were less phytotoxic to the crop than the postemergence applications. The broadleaved weeds were controlled by imazaquin at 0.20 and 0.25 kg/ha at 60 days after application. Fomesafen showed similar performance at 40 and 60 days, and acifluorfen at 40 days. The narrowleaved weeds were controlled by acifluorfen at 40 and 60 days after application.