Selectivity and efficacy of herbicides used on wheat to control ryegrass.

Weeds, especially ryegrass (Lolium multiflorum), interfere with and at the same time reduce the productivity and grain quality of wheat. The objective of this study was to evaluate the selectivity and efficacy of pre-emergent herbicides used in combination with post-emergent herbicides on wheat to control ryegrass. Two experiments were conducted in a randomized block design with four replicates, one to check selectivity and the other to assess ryegrass control. The variables evaluated were: herbicide phytotoxicity to wheat, ryegrass control, number of ears per area, hectolitre weight, thousand-grain mass and grain yield. The results indicate that pinoxaden showed low phytotoxicity to the crop and high control of ryegrass. S-metolachlor showed phytotoxicity, increasing with higher doses. The application of S-metolachlor + pinoxaden (480 + 40 g ha-1) resulted in the highest grain yield for the TBio Duque and TBio Sossego wheat cultivars. The use of pinoxaden in isolation shows better performance of the grain yield components of the TBio Duque and TBio Sossego wheat cultivars. [ABSTRACT FROM AUTHOR]