Toxic effects of the crude methanolic extract of <i>Austroplenckia populnea</i> leaves and fractions on the growth of <i>Spodoptera frugiperda</i>

Abstract

The aim of the current study is to assess the toxicity of <i>Austroplenckia populnea</i> leaf extracts towards the <i>Spodoptera frugiperda</i> population in laboratory conditions. Initially, a crude methanolic extract was obtained from dried leaves of <i>A. populnea</i>. This extract was fractionated using hexane, ethyl acetate, and then methanol. Neonate <i>S. frugiperda</i> larvae were isolated in plastic containers and fed (once) on corn leaf fragments treated with crude and fractions of the investigated plant extracts. The life cycle of the larvae treated with the extracts was monitored. In addition to the intake of leaves treated with the plant extracts, such variables as larval and pupal mortality rate, larval and pupal weight, and larval, pupal, and adult stage duration were evaluated. The crude, hexane, and methanol extract fractions exerted an antixenosis effect on the feeding behaviour of neonate <i>S. frugiperda</i> larvae. A significant antibiosis effect was observed for the hexane fraction of the <i>A. populnea</i> extract, since all of its concentrations promoted a <i>S. frugiperda</i> larval mortality rate differing from that observed for the control. The pupal mortality rate was low, but it did not differ significantly from the mortality rate observed for the control treatment, which was nil. The larvicidal effect of the <i>A. populnea</i> leaf extract, mainly of its hexane fraction, has indicated its potential to be used in integrated <i>S. frugiperda</i> management programs.