COMPATIBILIDADE E TOXICIDADE DE MISTURAS DE INSETICIDAS QUÍMICOS E BIOLÓGICO USADOS NO CONTROLE DE Anticarsia gemmatalis

Abstract

Aiming at saving and optimizing the application, it is necessary to use product mixtures in the spray tank. However, there is little information about the interaction between the compounds in the mixture and which can affect its performance in the field. For this reason, this work aimed to evaluate the effectiveness of the mixture of chemical insecticides with the bioinsecticide B. thuringiensis and its lethal effects on Anticarsia gemmatalis, an important soybean pest that can lead to complete defoliation of the crop. Two tests were performed, the in vitro compatibility test and the Anticarsia gemmatalis mortality test. The treatments used for in vitro compatibility were: only the bioinsecticide B. thuringiensis (control); and bioinsecticide B. thuringiensis added to chemical insecticides; Methomyl; Chlorantraniliprole; Lambda-Cyhalothrin + Chlorantraniliprole; Cypermethrin, totaling 5 treatments. The completely randomized design was obtained through these 5 treatments, with 6 repetitions per treatment, and the average of the colonial area obtained from the 3-day analysis. After analyzing the size of the colonies developed on the plates, using the ImageJ software, there was a significant difference (p<0.05) between treatments for the colony area formed on the plates. The treatments for the mortality test consisted of combinations of the bioinsecticide B. thuringiensis with the same chemical insecticides (with the exception of the cypermethrin-based insecticide), the bioinsecticide alone and also the chemical insecticides alone, totaling 8 treatments. the completely randomized design was obtained through these 8 treatments, with 5 repetitions per treatment, containing 8 caterpillars per repetition, and the analyzes lasted three days. The mortality of the treatments was also compared by Time Lethal (TL50). As a result, the Methomyl-based active insecticide is compatible with Bacillus thuringiensis, preserving the high efficiency of the two active principles in controlling A. gemmatalis. Cypermethrin-based insecticide is incompatible with Bacillus thuringiensis indicated by low colony growth. The Methomyl-based insecticide, used alone or mixed with the bioinsecticide, causes more rapid mortality of Anticarsia gemmatalis than the other insecticides tested. The insecticide based on Chlorantraniliprole, when mixed with the bioinsecticide, delayed the mortality of A. gemmatalis, indicating a negative effect of the mixture in relation to the mean, and not in relation to the Lethal Time interval. The mixture of the insecticide based on Lambda-Cyhalothrin + Chlorantraniliprole with the bioinsecticide delayed the mortality of A. gemmatalis, indicating a negative effect of the mixture.