REAÇÃO DE DIGITARIA INSULARIS RESISTENTE AO GLIFOSATO A FITONEMATOIDES

Abstract

The Sourgrass (Digitaria insularis (L.) Fedde) is a weed difficult to control, especially problematic in the soybean-corn succession second crop, a situation that is aggravated by the direct planting system. The main control strategy is the use of herbicides, mainly glyphosate, however, recurrent use has led to the development of resistant biotypes. Sourgrass can act as an alternative host for nematodes and other species. The objective of this study was to analyze the hostability of D. insularis to Pratylenchus brachyurus, Heterodera glycines and Meloidogyne javanica, as well as to evaluate biotypes (natives of agricultural and urban areas) of D. insularis on dose-refueling curves of glyphosate and the basis of two morphophysiological and enzymatic indices. The Sourgrass D. insularis was shown to be susceptible to the nematoid P. brachyurus, while there was no indication of H. glycines reproduction and M. javanica shown to be aggressive, highlighting the enzymatic response of plants to the stress caused by P. brachyurus, observing variable enzymatic activity (PAL, LOX, GLU) in inoculated plants, evidencing defense. The D. insularis, even in urban areas, demonstrate low sensitivity to glyphosate.