Selectivity of herbicides applied in pre and post emergence of safflower culture

Abstract

The cultivation of safflower has increased in recent years, mainly for the production of biodiesel. However, it is necessary to weed control in order to avoid losses in productivity. In this way, an alternative that comes up is the use of selective herbicides for culture. This study aimed to verify the selectivity of different herbicides in pre and post-emergence to the safflower crop. Two experiments were conducted adopting a randomized block design with four replicates. For the first experiment with pre-emergence applications the treatments were arranged in a 6 x 2 + 1 factorial scheme, whereas for the second experiment with the post-emergence applications the treatments were arranged in a factorial scheme 7 x 2 + 1. For both experiments, the factor A corresponded to the different herbicides and factor B at the doses used and the additional treatment consisted of control without application of herbicides. Visual evaluations of intoxication were carried out in the plants at 7, 14 and 21 days after application (DAA), plant height, stand and productivity. The application of chlorimuron-ethyl (20 e 40 g i.a. ha-1), flumioxazin (50 e 100 g i.a. ha-1), imazaquin (161 e 322 g i.a. ha-1), s-metolachlor (1440 e 24000 g i.a. ha-1) and sulfentrazone (300 g i.a. ha-1) in pre-emergence, and sethoxydim (184 g i.a. ha-1), fluazifop-p-butyl (375 e 750 g i.a. ha-1) haloxyfop-methyl (60 e 120 g i.a. ha-1) e clethodim (108 g i.a. ha-1) in post-emergence were selective for safflower.