Consumo foliar da Rachiplusia nu (Lepidoptera: Noctuidae) em variedade de soja (Glycine max) tratada com bioinsumos

Abstract

Worldwide, soy plays its role as a crucial source of food, animal feed and biofuels for an ever-expanding global population. However, intensification of agricultural production is often associated with significant use of chemical pesticides for pest control, which can have adverse impacts on the environment and human health. Given the growing population of the Rachiplusia nu caterpillar, a pest that has threatened soybean plantations for the past few years, the study proposed two stages, the first being the production of soybean leaves to study the caterpillar's leaf consumption. We then evaluated two stages of development with the provided bioinput treatment sheets, with three biological treatments and the control (without application of bioinputs). The mixtures with biological insecticides were prepared with the microorganisms, the fungus Metarhizium anisopliae, the bacteria Bacillus thuringiensis (Bt) and the AcMNPV virus (Autographa californica Multiple nucleopolyhedrovirus), the leaf consumption area data were subjected to the Shapiro-Wilk and Levene tests and for not Meeting the ANOVA assumptions, the Kruskall-Wallis non-parametric test was performed, and there was a significant difference between the means of caterpillar consumption. In the second stage, consumption was lower than in leaves treated with microbiologicals. In the fourth instar, the opposite occurred, with leaf consumption being lower in treated leaves. All treatments used to evaluate leaf consumption successfully controlled R. nu. All biological treatments used caused the mortality of the caterpillars, which presented symptoms typical of each microbiological treatment. It is noteworthy that the BRS 534 soybean variety showed natural resistance to the pest, which can possibly be attributed to factors such as antixenosis and/or antibiosis. This finding reinforces the importance of the biological approach, highlighting not only the effectiveness of biological control, but also the existence of natural resistance characteristics in certain soybean varieties that are important in integrated indirect management.