Glyphosate and post emergence herbicides associations for controlling Commelina benghalensis on soybean RR®

Abstract

This research aimed to evaluate the selectivity and efficacy of glyphosate tank mixture with different post- emergent herbicides on controlling Commelina benghalensis in soybean RR^® crop. The experiment was conducted in field conditions using complete randomized block design, with four replications, where the treatments were four rates of cloransulam-methyl herbicide (10, 20, 30 and 40 g ha^-1), four rates of chlorimuron-ethyl herbicide (2.5; 5.0; 7.5 and 10 g ha^-1), imazethapyr at 100 g ha^-1 and lactofen at 72 g ha^-1, all in association with glyphosate herbicide at 960 g ha^-1. It was also included three controls, characterized by an isolated rate of glyphosate at 960 g ha^-1, a sequential application of glyphosate at 960/ 960 g ae.ha^-1 besides a check without weeds handle control. The results obtained showed that only the unique application of glyphosate herbicide at 960 g ha^-1 and its association with the lower rate of cloransulam-methyl (10 g ha^-1) or chlorimuron-ethyl (2.5 g ha^-1) did not promote effective C. benghalensis control. All chemical treatments did not influence soybean RR^® yield, although the association of glyphosate and the higher rate of chlorimuron-ethyl (10 g ha^-1) have promoted significant reduction in 1000 soybean grains weight.