INDUÇÃO DE RESISTÊNCIA EM CULTIVARES DE Zea mays L. A Spodoptera frugiperda (Lepidoptera: Noctuidae)

Abstract

Zea mays L. maize is one of the world's major cereals. Although Brazil is one of the largest producers in the world, it still faces serious problems and limitations in cultivation, mainly due to the insect pest attack, among the pricinpals of the carcass caterpillar Spodoptera frugiperda. The objective of this work was to evaluate the induction of resistance in maize cultivars after the application of Silicon and Calcium sources in the infestation of the S. frugiperda caterpillar. The experiment was conducted at the Chã de Jardim experimental farm, belonging to the CCA-UFPB, located in the city of Areia-PB. Two cultivars of Zea mays maize were used: Hybrid AG1051 (Monsanto®) and cultivar Potiguar EMPARN®. These cultivars were submitted to two treatments of foliar fertilization, calcium chloride and potassium silicate, and a control treatment. The evaluations of the damages caused by S. frugiperda were carried out weekly, from the seventh day after the first application of the products (Si and Ca). In the maize (VT) phase, the gas exchange and photosynthetic efficiency of the leaves were evaluated. Fluorescence of Chlorophyll a, was determined. Damage probability data were submitted to multinomial distribution analysis. The percentage of infestation and data related to the gas exchange were submitted to analysis of variance, and the means of the treatments were compared by the Tukey test, at a probability of 5%. For the genotype Potiguar, there were predominant plants that did not present any type of damage. The Potiguar genotype showed the lowest means of infestation by S. frugiperda, regardless of the product applied. There were no statistical differences between the products applied between each genotype. The data of maximum quantum efficiency of FSII (FV / FM) were not statistically significant for the cultivars nor for the interaction cultivars x treatments. For the EC, a statistical difference between cultivars was found. In the Potiguar, higher results were obtained in relation to GA 1051. The variable TF did not present statistical difference between the evaluated cultivars. Different behaviors in T between cultivars were observed in Potiguar when submitted to silicon application and in the control, greater transpiration was obtained when compared to genotype AG 1051. Regarding the physiological parameters of IC, DP, EFUA and EC, no significant differences were observed between the evaluated cultivars and the evaluated treatments. The Potiguar variety of Zea mays suffered less injury from the infestation of S. frugiperda compared to the Hybrid AG 1051. The sources of Silicon and Calcium did not promote the induction of resistance to S. frugiperda in the maize cultivars evaluated.