Antifeedant activity and effects of fruits and seeds extracts of Cabralea canjerana canjerana (Vell.) Mart. (Meliaceae) on the immature stages of the fall armyworm Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae)

Abstract

The biological activity of ethyl acetate and ethanolic fruit and seed extracts from Cabralea canjerana on eggs, larvae and pupae of the fall armyworm (FAW) (Spodoptera frugiperda) was evaluated. Silica gel column chromatography fractionation of the most active extract, the ethyl acetate seed one, yielded five fractions whose bioactivity was also evaluated. All extracts showed high larvicidal and antifeedant activity at the highest evaluated concentration. They also altered significantly the life cycle of the FAW, the larval weight, and induced various larval and pupal abnormalities. The most active fraction, mainly composed of triterpenes, at 165mg/kg, killed 60% of the larvae. The main component from this fraction was isolated and characterized, resulting in a new dammarane triterpene, ocotillone 7,15 diol. The extracts and fractions as a whole, showed higher activity compared to toxicity values from the isolated compounds from C. canjerana to FAW reported in the literature. Moreover, as C. canjerana is distributed throughout the Americas and its extracts showed a promising biological activity with Category III toxicity level, according to the OECD 425 assay, they could be used as a potential natural pesticide.