Imazapic effectiveness in itchgrass control applied in different soil textures

Abstract

Itchgrass (Rottboelia exaltata L.f.) is a weed that presented fast dissemination in sugarcane fields in Brazil, causing significant yield losses to the crop. Therefore, this research had the objective of evaluating the susceptibility of the weed itchgrass to imazapic when applied in pre-emergence using dose-response curves. The experiments were carried out in randomized blocks experimental design with four replications in a factorial arrangement between two soil (clayey-sandy and sandy) and nine rates of imazapic. The herbicide rates were: 0; 9.19; 18.38; 36.75; 50; 73; 147; 294; 588 and 1176 g a.i. ha^-1 and check without application. The sandy soil scored by visual control upper and lower levels of residual dry matter compared to the clayey-sandy soil. Soil texture has a direct influence on the effectiveness of control. Soil texture has a direct influence on control efficiency, so that the dose of 18.38 g a.i. ha^-1 showed more control of itchgrass in sandy soil, while for clay and sandy soil was 294 g a.i. ha^-1. Control levels indicate that application of imazapic in pre-emergence is viable to control the weed itchgrass.