Control of silverleaf whitefly in cassava grown in the greenhouse treated with Anacardium humile (Anacardiaceae) extract

Resumo

Bemisia tuberculata (Bondar, 1923) is the most important pest of cassava crops. This work describes the effect of different concentrations of CHCl3 extract from the leaves of Anacardium humile in relation to Bemisia tuberculata, under laboratory conditions, in cassava plants and chemical composition of this extract. Fractionation of the CHCl3 extract yielded the triterpene acids: oleanolic, ursolic and betulinic. Their structures were determined on the basis of spectral data (NMR-1D and 2D) and subsequent comparisons with the literature. Anacardic acid was identified in CHCl3 extract by high performance liquid chromatography (HPLC). CHCl3 extract caused mortality of whitefly nymphs of B. tuberculata from 66.30 to 74.90%, in doses tested. The insecticidal activity of CHCl3 extract of A. humile on the nymphs of the whitefly suggests that pentacyclic triterpenes and anacardic acid have potential insecticidal activity.