Influence of different post-emergence application times of chlorimuron-ethyl, fomesafen and bentazon herbicides on the control of Commelina benghalensis L

Abstract

The aim of this research was to study the influence of different application times on the uptake and efficiency of chlorimuron-ethyl, fomesafen and bentazon herbicides. The experiment was carried out at Universidade Estadual de Maringá to evaluate the most appropriate conditions of temperature, relative humidity and light to control Commelina benghalensis L., by applying the herbicides at ten different times of the day. Weed control was evaluated at 7, 14 and 21 days after application (DAA). The results indicated that at 7 DAA chlorimuron-ethyl provided lower control at the intervals from, 11:30p.m. to 5:30 a.m. and from 11:30p.m. to 5:30p.m. At 14 DAA and onwards the product showed satisfactory results for all times of application. As for fomesafen and bentazon, at 7 DAA, the times of minimum control were 11:30 a.m. and 5:30 p.m. Therefore, in order to reach maximum control of Commelina benghalensis L., the hours of the day when temperature and relative humidity are lower than 18ºC and 50% should be avoided.