Potencial de Phoma conyzaphthora para o controle de buva (Conyza bonariensis e Conyza canadensis) em pré-emergência

Abstract

One of the factors that limit agricultural productivity in the current scenario worldwide are weeds, directly interfering and influencing large crops produced significantly in losses in quality and productivity. The horseweed (Conyza bonariensis and Conyza canadensis) is one of the most harmful weeds in Brazilian agriculture, being quite aggressive, easily distributed, they are annual plants characterized as winter and summer species. The indiscriminate use of chemical herbicides, mainly glyphosate, to control these species increased the selection pressure, gaining in the selection of resistant resistant ones. It is essential to search for alternative means of control, such as biological control, which is an excellent option to the use of chemical herbicides. The objective of this work was to evaluate the potential of Phomaconyzaphthora isolates for the control of horseweed (Conyza bonariensis and Conyza canadensis) in pre-emergence. Four isolates were used (isolates COAD 1066B, COAD 2380C, COAD 2383A and COAD2383C). Suspensions prepared with fragments of mycelium at a concentration of 1x106 fragments/mL, with crushed rice at a concentration of 50% m/v and fragments of mycelium at concentrations of 2.5%, 5%, 7% and 10% m/v and of fungus filtrate. The experiments were set up in a completely randomized design (DIC). The treatments of the fungus COAD 1066B that followed the highest tendency of germination of the seeds of C. canadensis were those in the concentration percentages of 2.5%, 5%, 7.5% and 10% m/v, being that the treatment in the concentration 2.5% was better for monitoring seed germination. For the treatments carried out with mycelium fragments at a concentration of 1x106 fragments/mL, the COAD 1066B treatment was the best to inhibit the germination of C. bonariensis. Phoma conyzaphthora isolate COAD 1066B has potential as a biological control agent in C. bonariensis and C. canadensis species.