Fungicidas biológico e químicos no controle de doenças da soja

Abstract

Soybean is a crop widely cultivated during the summer in almost the entire Brazilian territory and plays a key role in agribusiness. It has several disease-causing agents, which cause loss of agricultural productivity, thus, it is necessary to adopt an integrated management of diseases, and fungicides and/or biological agents can be used. This work aimed to carry out the practice of chemical and biological control, with the use of different active principles and/or biological agents, for the control of anthracnose, Asian soybean rust and target spot. The use of biological agents in the control of plant diseases is a promising alternative, as it presents specificity to the target, using different means to reach it, restricting the chances of selecting resistant strains. The objective was which treatment would present the best result, in terms of greater productivity and better disease control. The experiment was demarcated in a soybean area already implanted in FAECA, when in the V3-V4 stage, in a randomized block design with 6 treatments and 4 replications. The treatments were: control without fungicide application, Cyproconazole + picoxystrobin, Bacillus amyloliquefaciens + Cyproconazole + picoxystrobin, Trifloxystrobin + Cyproconazole, Bacillus amyloliquefaciens + Trifloxystrobin + Cyproconazole, Bacillus amyloliquefaciens. The applications were: microbiological in V5, microbiological + chemical in R1 and microbiological + chemical in R4. In the experiment, the following characteristics were evaluated: pods per plant, grains per pod, plot mass, thousandgrain mass and yield. As a result, there was a low incidence of diseases due to climatic conditions, in which Asian rust presented low severities in the initial stages of the crop, and in the final stages there was the occurrence of gray rot. The variable mass of one thousand grains was positively correlated with soybean yield, however, there was no significant effect of chemical and biological fungicide treatments on the characteristics evaluated.