Anomalias nas espigas e plantas de milho submetidas a diferentes combinações de produtos fitossanitários, adjuvantes e fertilizantes foliares, aplicados em V15 e R2

Abstract

The application of chemicals in maize is essential to ensure high yields, since several phytopathogens decrease the photosynthetic area of the plants. However, in 2007, in the United States, an anomaly related to the ear malformation of corn plants, called "arrested ears", spread through several crops when they were submitted to applications of different chemical products. This, which also affected the Brazilian fields in the agricultural year 2017/2018. Therefore, the objective of this work was to reproduce the phenomenon of anomaly in corn plants when submitted to combinations of different phytosanitary products, adjuvants and foliar fertilizers in different phenological stages. The experiment was conducted in Uberlândia - MG, during the second harvest of 2018. Two field trials were carried out, comprising two different application times, characterized by the phenological stages V15 and R2. The experimental design was a randomized block with eight treatments and seven replicates. One control and the other composed of different phytosanitary products were: fungicide (triazole + strobilurin + carboxamide), mineral oil, insecticides, adjuvant, orange essential oil and foliar fertilizer, in which in a treatment, the dose recommended by the manufacturer of the products was doubled. Plant height, ear insertion height, percentage of faulty ears, grain yield, grain weight per ear and weight of one thousand grains were evaluated. It was observed that when the chemicals were applied in the first application period (V15), the percentage of defective ears was higher in the treatment in which the dose of the chemical was doubled, resulting in lower grain yields, ear and weight of a thousand grains. In relation to the second application period (R2), no differences were observed in the percentage of defective ears, with the addition of leaf fertilizer responsible for higher yields, grain weight per ear and weight of one thousand grains. For both times of application, treatment that doubled the dose of products, obtained lower heights.