Resistência de capim-arroz ao herbicida quinclorac em Santa Catarina

Barnyardgrass (Echinochloa spp.) infestation is very high and results in significant yield losses inpaddy rice in Santa Catarina State. The objective of this study was to evaluate quinclorac resistance of Echinochloa spp. ecotypes in rice fields and to test the susceptibility of these populations to herbicides bispyribac-sodium andcyhalofop-butyl. Three barnyardgrass populations were evaluated: ECH 33, ECH 37 and ECH 38, compared to a resistant (ECH 13) and a susceptible (ECH 17) ecotype. The experiment was carried-out in a greenhouse. Herbicide treatments were: quinclorac, cyhalofop-butyl and bispyribac-sodium. The ecotypes ECH 38 and ECH 13 are resistantto quinclorac, but ECH 17, ECH 33 and ECH 37 are susceptible. Ecotypes ECH 38 and ECH 13, resistant toquinclorac, are controlled by cyhalofop-butyl and bispyribac-sodium.