Effects of different soil water status on the herbicides action in plants of Bidens pilosa

Abstract

The aim of this study is to assess the effectiveness of herbicide control of chlorophyll biosynthesis inhibitors (saflufenacil) and inhibitors of enol piruvil-shikimate-phosphate synthase, EPSPs (glyphosate), applied in post-emergence on Bidens pilosa, maintained at different water contents in the soil. The experiment will be carried out at the Department of Plant Production, Faculty of Agricultural Sciences / UNESP, Botucatu / São Paulo. The seeding will be done in 2 L pots, which will be pre-dried and its water retention curve measured by keeping them in a green house. After the emergency will be made a looping, leaving one seedling per pot. The design will be the completely randomized design with four replications, consisting of a 3x3 factorial design, with three water management systems (-0.03, -0.07 and -1.5 MPa) and three applications of herbicides (saflufenacil, glyphosate and saflufenacil + glyphosate) in recommended doses of each product. Herbicide application will be done when the plant is 6-8 with leaves. The water management strategies will be initiated in the development stage of two leaves, water for replenishing the soil reaches the potential of -0.01 MPa when the voltage reaches predetermined. Will be evaluated stomatal conductance, and dry plants. The visual assessment of control will be performed at 7, 14 and 21 days after application. The results of chemical control and other evaluations will be submitted to analysis of variance by F test and means were compared by Tukey test at 5% probability. (AU)