Resistência do milho crioulo à lagarta do cartucho com aplicação de silício

Abstract

Considered one of the main pests of corn, the fall armyworm Spodoptera frugiperda (Lepidoptera, Noctuidae) feeds on younger leaves, in addition to destroying the central ones. When silicon is applied, this element is transported in greater quantities in the aerial part of the plant and deposited in the epidermal cells as amorphous silica (SiO2.nH2). The application of silicon makes feeding the caterpillars more difficult, causing greater mortality and cannibalism, therefore, the corn plants become more resistant to the fall armyworm. Thus, the objective of this work was to evaluate the resistance of the fall armyworm to the application of silicon in varieties of native maize. A 5% dose of potassium silicate was used, which were applied to two varieties of creole corn: popcorn and red. The corns were cultivated in the greenhouse for fifteen days. The caterpillars were fed in the seed laboratory of the Federal University of Mato Grosso and separated into four groups of ten, the first group were fed popcorn corn without silicon, the second popcorn corn with silicon, the third red corn without silicon and the fourth red corn with silicon being used ten caterpillars per treatment in a completely randomized design and the data analyzed by the F test comparing the treatments without and with silicon, because they are varieties with different purposes, comparisons between varieties were not made. After ten days, the first weighing of the caterpillars and later the pupae was carried out. The results indicate that there was no influence of the application of silicon on the weight of caterpillars and pupae regardless of the application of silicon: Caterpillars Red without silicon (245+ 41.7 mg), Red with silicon (281.0+ 322 mg); Popcorn without silicon (221+ 52 mg), and Popcorn with silicon (207.5+ 55.2 mg); pupae, 117; 102; 112.2 and 112 mg, respectively. However, higher mortality was observed in the cultivar Vermelho without silicon (50%) than in the others, Vermelho with silicon (10%); Popcorn without silicon (0%), and Popcorn with silicon (10%).No harmful effects of fertilization with a silicon source were observed on the biological parameters of Spodoptera frugiperda.