Aplicações de fungicidas no estádio V4 e seu impacto no manejo de doenças e na produtividade da cultura do milho

Abstract

Helminthosporiosis (Exserohilum turcicum) found in the off-season harvest a favorable environment to develop, high humidity and temperature between 18 and 27 ºC, affecting the crop in its first vegetative stages, and presenting rapid growth of lesions, which can occupy large areas of leaf tissue in little time. At the same time, the four-leaf defoliation and the total defoliation in the V4 stage of the crop, presented reductions of around 6.25 and 14.05%, respectively, in productivity. Thus, the objective of this work was to evaluate the addition of a fungicide application at stage V4 and its impact on the management of foliar diseases and on maize crop yield. Two trials were carried out under field conditions, in Uberlândia, at an altitude of 850 m, during the first crop of the 2020/2021 agricultural year. For the trials, randomized block experimental design (RB) was used, and carried out on the commercial hybrid NS73 VIP3. Trial 1 had three treatments and nine replications, formed by different combinations of commercial fungicides based on triazoles, strobilurins and isophthalonitriles, applied at different times. Trial 2 had three treatments and thirteen replications, using different arrangements of fungicides based on triazoles, strobilurins, benzimidazoles and isophthalonitriles, applied at different times. The application of foliar fungicides reduced the severity of foliar diseases, which resulted in an increase in productivity. The tests showed that the addition of a fungicide application in the first stages of the corn crop, either with Propiconazol + Cyproconazol or with Tebuconazol + Carbendazim, provided a greater control of foliar diseases.