Eficiência do fungicida piraclostrobina + epoxiconazol no controle de doenças foliares do milho

Abstract

The importance of the pathogens that infect corn crop has increased in recent years, constituting a major obstacle to the continuous increase in productivity. To evaluate the efficiency of chemical control of maize’s diseases conducted an experiment in the municipality of Manoel Ribas, PR. The work consisted of five treatments (T1 = witness; T2 = 1 application of pyraclostrobin + epoxiconazole 0,75 L ha-1 (tractor’s limit); T3 = 2 applications of pyraclostrobin + epoxiconazole 0,5 L ha-1 (1st application within the tractor’s limit and 2nd in the pre - tasseling) and T4 = 1 application of pyraclostrobin + epoxiconazole 0,75 L ha-1 (pre - tasseling) and T5 = 2 applications of pyraclostrobin + epoxiconazole 0,75 L ha-1 (1st application at the tractor’s limit and 2 nd in the pre - tasseling); with 4 replications, totaling 20 experimental units. The experimental design was randomized blocks, were the experimental unit consisting of plots with four rows with spacing between rows of 0,7 and 5 m in length. The products were applied by spraying the constant pressure of CO2 (25 kgf cm-3). Analyzed variables were: number of rows per ear, ear length (cm), hectolitre weight, percentage damaged kernels, severity AUDPC common corn rust, leaf spots, gray leaf spots and white spot, beyond the yield in kg ha1. The information was subjected to analysis of variance by F test, and their means compared by Tukey test at 5% probability. Considering the values of AUDPC concluded that the application of fungicide was effective in controlling common rust, gray leaf spot and maize’s leaf spot, noticed also that for the control of white spot there was no difference between treatments. Although treatments have reduced the symptoms of nearly all diseases studied, this was not reflected in grain yield.