Ação de bactérias isoladas do Nim sobre adultos de Spodoptera frugiperda

Abstract

The objective of this work was to evaluate the fecundity and fertility of adults of Spodoptera frugiperda after ingesting in the larval phase bacteria isolated from the neem plant, Azadirachta indica. Eleven bacterial isolates were evaluated with the suspensions calibrated at the concentration of 5.0 x 108 cells / mL. The calibration was done in a spectrophotometer adjusted to 540 nm of optical density. Suspensions were used to treat fragments of corn leaves that were offered as feed for newly hatched caterpillars of S. frugiperda. Control caterpillars received untreated corn leaves. With the surviving adults of these caterpillars were formed couples who were kept in cages. The longevity of males and females, pre-oviposition period and fertility, number of days of oviposition and total postures, fertility and fertility of females were evaluated. Of the total number of isolates evaluated, 64.0% of them had an adverse effect on adults, to the point of affecting one or more of the evaluated variables. Intake of bacteria by caterpillars reduced adult, male and female longevity. The females had a reduction in the fertile period, number of postures, fecundity and fertility. Only the pre-oviposition period was not affected. The isolates Bacillus sp. Epi 9, Bacillus subtilis and Nim 10 were highlighted, therefore, they affected the largest number of variables evaluated. The results obtained in this work are promising and important, because this is the first report of bacteria isolated from neem with pathogenic action to adults of S. frugiperda.