Manejo sustentável da cigarrinha-do-milho: integrando inseticidas biológicos e químicos

Abstract

Corn is the most produced cereal in the world, and because it is cultivated in more than one season in practically all regions of Brazil, it provides suitable conditions for the occurrence and attack of the corn leafhopper Dalbulus maidis (Hemiptera: Cicadellidae). The corn leafhopper is currently one of the main corn pests, especially because it is responsible for the transmission of mollicutes and virus. Its management is carried out mainly with chemical insecticides, usually with a large number of sequential sprays. Because management is largely based on the use of chemical insecticides, there is an interest in developing more sustainable alternatives for the management of this pest, with biological insecticides being the most promising alternative. This dissertation aimed to evaluate chemical and biological insecticides, combined in sequential applications, featuring three management programs: biological, chemical and biological - chemical in four areas of the state of RS. The applications started with the verification of the pest in the area, with an interval of 7 days until the culture reached grown stage V10. The results were submitted to analysis of variance (ANOVA) and Scott-Knott test (P≤0.05), revealing differences between treatments. The results of the three experiments, that had a significant presence of corn leafhopper, showed that biological insecticides have efficacy between 36% and 57%, while chemical insecticides have efficacy between 49% and 72%. The management program with biological - chemical applications presented control between 48% and 67%, not statistically different from the exclusive chemical management and characterizing an alternative control for corn leafhopper.