SENSIBILIDADE DE ISOLADOS DE Colletotrichum spp. ORIUNDOS DE SOJA Á MISTURA DE FUNGICIDAS

Abstract

Anthracnose is a disease that causes severe damage to soybeans, is the main disease that affects the formation of pods, can cause seedling death and black spots on the leaves, stems and pods. In the Cerrado the highest incidence of the disease occurs mainly due to high precipitation and high temperature. The difficulty in controlling the disease can be attributed to the selection pressure promoted by fungicides in agriculture that stimulates pathogen variability mechanisms to develop populations insensitive to chemical molecules. Today, contact and systemic fungicide mixtures are recommended as they provide the most effective protection against major soil fungi such as Colletotrichum truncatum. The objective of this work was to evaluate in vitro the sensitivity of different isolates of C. truncatum collected at different sites, which belong to the Mycological Collection of the Federal Institute Goiano - Campus Urutaí, to fungicides of different active ingredients, incorporated into BDA at concentrations of 0; 0.1; 1.0; 10 and 100 ppm. The percentage of conidial germination of the fungus was evaluated when submitted to the fungicides: Ativum (piraclostrobin + epoxiconazole + fluxapiroxade), Orkestra (fluxapiroxade + piraclostrobin) and Fox (protioconazole + trifloxystrobin) to establish which one had the highest control efficiency. He found that the progressive increase in doses promotes reductions in mycelial growth. The IF15 isolate was confirmed by both the area below the mycelial growth progress curve and the mycelial growth rate, as sensitive to all fungicides studied. It can verify the great variability of sensitivity of C. truncatum isolates with different molecules and the importance of detection of resistant populations.