Eficiência de fungos entomopatogênicos para o controle de ninfas de Bemisia Tuberculata (Bondar, 1923) (Hemiptera: Aleyrodidae) em cultivo de mandioca

Abstract

The aim of this study was to evaluate the pathogenicity of entomopathogenic fungi in controlling the cassava whitefly. The tests were carried out at a commercial area of cassava "spit" variety at Barra Bonita farm, Dourados-MS. We used a randomized block design with 7 treatments and 4 replications, totalizing 28 plots. The treatments were: control, Metiê ® (active ingredient Metarhizium anisopliae) with 1, 2 and 3 applications, Bioveria ® (active ingredient Beauveria bassiana) with 1, 2 and 3 applications. Evaluations were performed 21 and 28 days after spraying and in each plot were observed and recorded the average number of live and dead nymphs (with confirmed mortality). Means were compared by the Scot-Knott test at 5% of probability and efficiency was calculated by the Abbott formula. The data were transformed into (x + 0.5)½ and subjected to analysis of variance. In the first evaluation, all the treatments significantly differed from the control, but did not differ one from the other. However, treatment Ma 1 (Metiê ® with 1 aplication) provided better control observed due to the lower number of nymphs of B. tuberculata. In the second evaluation there were no significant difference among the treatments, but , treatment Bb1 (Bioveria ® with 1 application) provided the lowest number of nymphs showing a reduction of 44.7% compared to the living population of nymphs on the control treatment. Treatments based on the fungus Beauveria bassiana were those which provided a greater number of nymphs killed in the first and second evaluation. The Bioveria ® insecticide with one application was most effective when compared to the other, which killed the nymphs in 61.4 and 64.9% at 21 and 28 days after application, respectively.