WEED KILLING EFFICACIES OF HERBICIDES AS AFFECTED BY APPLICATION TIMES IN WHEAT

Abstract

The biological efficacy of different herbicides (Sencor 7 WGJ SOOg ha 1 . Lintur 70 WG 250g hi'. Ronstar @ Iliter ha 4 ) applied at different stages of crop growth as compared to untreated areas was studied for controlling weeds in wheat in a field experiments at the research farm of Sher-e-Bangla Agricultural University during 2007- 08. Herbicides were applied at 7 DAS, 14 DAS and 21 DAS. A weedy check (no herbicide) was also included for comparison. The analysis of the data revealed significant differences among the times of application for biological yield and grain yield. Similarly significant differences were recorded for herbicidal treatments in traits like 1000 grains weight (g), biological yield (t ha 1 ) and grain yield (t ha 4 ). The interaction of the times of application and herbicides was significant for grain yield. Maximum 1000 grains weight (47.48g) was observed in plots treated with Ronstar, while minimum check plots (no herbicide). Biological yield (38.17g) in weedy (7.0 t hi') and grain yield (3.16 t ha 1) were higher in plots treated with Ronstar while lower biological yield (4.5 t hi') and grain yield (1.62 t ha4 ) were in weedy check plots. Ronstar proved to be the most economical and effective herbicides which gives maximum grain yield of yield (7.3 t hi'), when applied at 21 DAS in wheat.