Eficiência da aplicação de fungicidas foliares na redução do potencial de inóculo do fungo Fusarium spp. nos grãos de milho (Zea mays)

Abstract

Corn is among the most produced cereals in the world, and its economic importance is given due to its high rate of grain production and the various forms of its use. In view of this, it is essential that the production be of excellent quality and quantity, but one of the factors that affect these aspects is the presence of diseases in the crops, among which are the fungi of the genus Fusarium spp. The objective of this work was to test different positions for two fungicides indicated for the corn crop, evaluating the efficiency of the products for the control of Fusarium spp. in the grains. The experiment was carried out at the Federal Technological University of Paraná, and had three stages. In the first one, the initial sanity test of the implanted seeds was carried out. In the second stage corn was planted, where the plots were assembled with 5 rows of maize each, spacing 0.45 meters between rows, and 10 meters long, with a randomized block design with 4 replications. The treatments were: 1-V8 application of Azoxystrobin + Ciproconazole; 2 - VT application of Azoxystrobin + Ciproconazole; 3 - V8 + VT applications of Azoxystrobin + Ciproconazole; 4- VT application of Azoxystrobin + Ciproconazole + Mancozeb; 5- V8 + VT applications of Azoxystrobin + Ciproconazole + Mancozeb; 6- Witness. The third one evaluated the health of the harvested grains, exclusively evaluating the presence of Fusarium spp. Each seed within the gerbox was evaluated according to 4 levels of severity: a) inoculum potential null, b) low inoculum potential, c) potential medium of inoculum and d) high inoculum potential. For the statistical analysis, a contingency table (or cross-table) was constructed and the Chi-square test was applied. Multiple comparisons were also made by the Friedman test using the agricolae package. In general, the best control results were obtained in the treatment of an application of Azoxystrobin + Ciproconazole at the V8 stage, however all the treated plots showed superior control data when compared to the control.