Maria Aparecida da Fonseca Sorace

Identificação e controle de biótipos resistentes de Digitaria insularis (L.) Fedde ao glyphosate

Some invasive species has shown potential to develop resistance to glyphosate herbicide in no-till areas. Herbicides inhibitors of ACCase enzyme may be an alternative control to Digitaria insularis (L.) Fedde. The objectives of this study were to identify the occurrence of resistance in D. insularis (L.) Fedde to glyphosate in tillage areas of the State of Parana, and find the appropriate clethodim doses for its control. Were conducted two experiments in a greenhouse in Bandeirantes-PR, where the first was the experiment conducted with the glyphosate herbicide and the second with clethodim herbicide. Seeds of D. insularis (L.) Fedde plants were collected from five different places, and dose response curves were obtained for resistance verification. The tested doses were equivalent to 0; 0.5; 1; 2; 3 and 4 times the recommended dose of herbicide. The plants had 15 to 20 cm high when the herbicides were sprayed. The results showed that D. insularis (L.) Fedde biotypes from Parana cities are resistant to glyphosate herbicide. Furthermore, it was found differentiated tolerance to the clethodim herbicide in the biotypes.