Influência de fungicida e adubação foliar em características agronômicas e sanitárias da cultura do milho

Abstract

What defines the maximum potential of a culture s production is the set of factors related to: the history of the area, the genetic material, growing practices, climatic conditions, etc. Among these practices, the availability of nutrients and the use of chemicals for protection against pathogens are highlighted. Therefore, the objective of the present work was to verify the influence of foliar nutrition and protection in eight maize hybrids with high productive potential. The experimental design consisted of blocks randomized in sub- plots with six replicates and a floor area of 12.48 m2. The plot was formed by the hybrids, which were submitted to eight treatments (subplots): control (no application); Leaf 1 (N (5%), P2O5 (8%), K2O (8%), Ca (1%), Mg ( 0.5%), S (2.5%), Zn (1%), B (0.5%), Mn (0.5%), Cu (0.2%), Fe (0.1% ), Mo (0.1%) - Dose: 1 L ha-1), Leaf 2 (30% of H3PO3 + 9% of Mn2 +, density = 1.45 g mL-1 - Dose: 2 L ha-1) ; Leaf 3 (1.5% Co + 15% Mo, density = 1.61 g mL-1 - Dose: 150 mL ha-1); Protection (azoxystrobin - 200 g L-1 + cyproconazole - 80 g L-1 - Dose: 300 mL ha-1 + Nimbus 0.5%); Leaf 1 + Protection, Leaf 2 + Protection, Leaf 3 + Protection. Four applications were made. Applications were initiated at the V8 stage and 21-day intervals. The variables analyzed were: gross productivity, damaged kernels, net productivity, percentage of useful leaf area, integrity of the roots, quality of stem and severity of diseases. It was concluded that fungicide protection was the factor that most contributed to the maintenance of the productive potential of the hybrids used. The nutrition of the leaf area by using manganese phosphite and cobalt + molybdenum based compounds may play an important role in maintaining the vegetative quality of roots and stem, and they also play a role, yet unknown in reducing the production of rotten grains.