CARACTERIZAÇÃO DE BIÓTIPOS TOLERANTES A HERBICIDAS E USO DE FONTES NITROGENADAS ASSOCIADAS A ACCase NO CONTROLE DE CAPIM AMARGOSO NO OESTE DA BAHIA

Abstract

The objective of this study was to map the occurrence of sourgrass biotypes with potential resistance to glyphosate in the micro region of western Bahia by making map of occurrence of resistance. Up consisted of the collection of biotypes D. insularis in western Bahia in July 2017, in areas where leaks have occurred control after application of the glyphosate in the two seasons leading up collections. The seeds of each biotype were collected from about 100 plants present in the stands and seeded in plastic containers with 1,5 L capacity, with 8 replicates. To perform the previous selection of biotypes with possible resistance to herbicides when more than 50% of the plants had 3 tillers was applied glyphosate herbicide (1080 g e.a. ha-1), clethodim (240 g i.a. ha-1) and haloxyfop (120 g i.a. ha-1). Evaluations were performed weekly, up to 56 days after application. At each evaluation period, phytointoxication notes were given to plants based on the Latin American Weed Association scale. At 35 DAA, total dry biomass analysis of the plants was performed. In a punctual way, D. insularis biotypes located at collection sites 14 and 18 presented a lower control response with the herbicide application Glyphosate. The D. insularis biotypes of the western Bahia region were controlled by the herbicides Haloxyfop and Clethodim. The herbicide Clethodim showed a higher control rate of bittergrass than haloxyfop.