Efficacy of reduced spectrum chemical insecticides on larval mortality of Omiodes indicata in the vegetative stage of soybeans

Abstract

randomized complete design with 5 treatments and 5 replicates was implemented. The reduced spectrum treatments were T1 Emamectin benzoate, T2 Lufenuron, T3 Spinetoram; broad spectrum treatment T4 Chlorpyrifos and T5 Control without application. The Shapiro-Wilks normality test was used for data distribution; if the result was positive, the analysis of variance was obtained using Tukey's test at 0.05 confidence; if the result was negative, the non-parametric analysis of variance was obtained using the Kruskal-Wallis test at 0.05 confidence. In the field, the intensity of parenchyma scraping (leaf damage), longitudinal measurement of larvae (determination of instars), quantification of live and dead larvae was evaluated in 4 monitoring periods: Before applications, 24 - 48 and 72 hours after applications, as well as enumeration of beneficial fauna before chemical interventions and at 72 hours after. These variables were supported by a leaf damage gradology, larval instar scale, Towsend-Heuberger formula to know the percentage of leaf damage, Sun-Shepard formula on the percentage of larval mortality. Lufenuron treatment was the most effective and efficient on larval mortality of Omiodes indicata from 24 hours after the chemical intervention, there was no reduction of beneficial fauna post-application.