AVALIAÇÃO DA EFICIÊNCIA DE FUNGICIDAS SISTÊMICOS ASSOCIADOS A MULTISSÍTIOS APÓS SIMULAÇÃO DE CHUVA NO CONTROLE DE MANCHA-ALVO (Corynespora cassiicola) NA CULTURA DA SOJA (Glicine max L. Merrill)

Abstract

The objective of this study was to analyze the efficiency of the fungicide azoxystrobin in conjunction with mancozeb and chlorotalonyl multisites after the simulation of rainfall in different periods to control the target spot in soybean. The experiment was carried out at the company Fortgreen Comercial Agricola S. A in the municipality of Paiçandu-PR. It was planted 5 seeds per pots of two kg, with the mixture of soil and sand in the proportion of 3:1, without any type of fertilization or chemical treatment. The experiment was carried out in a completely randomized design with 20 treatments and 5 replications and the applications were CO-₂, with 40 pressure bar in the cone-type nozzle, according to the recommended commercial dosages for the control Target spot. The fungicides azoxystrobin alone, azoxystrobin + mancozeb and azoxystrobin + chlorotalonil were used. After application, they were subjected to rain simulations lasting 15 minutes at an intensity of 1mm / min at different times 0.5; 1; 2 hours after application. Disease severity in the inoculated trifolium was analyzed and the Area Below the Disease Progress Curve (AACPD) was verified. The use of chlorotalonil fungicide without association with rain after application caused phytotoxicity in soybean crop. The application of azoxystrobin + mancozeb and azoxystrobin + chlorotalonil according to AACPD obtained significantly different results, whereas Mancozebe in combination with the systemic showed better control in disease progression. Rain was a factor that interfered with this efficiency, and wetness 0.5 hour after the application of multisite mancozenbe + azoxystrobin was a factor that interfered with the increase of severity.