Abstract

ROSSETTI, María R. et al. Biological activity of extracts of Melia azedarach on larvae of Spodoptera eridania (Lepidoptera: Noctuidae). Rev. Soc. Entomol. Argent. [online]. 2008, vol.67, n.1-2, pp.115-125. ISSN 0373-5680.

In the course of searching for plant chemicals with potential insecticide properties, the activity of Melia azedarach L. senescent leaf and ripe fruit extracts (2, 5 and 10%) was evaluated on larvae of Spodoptera eridania Cramer (Lepidoptera: Noctuidae). This polyphagous species is considered a sporadic pest on many important crops. Food consumption was assessed and an antifeedant index was calculated through choice tests. Also, food consumption, larval mortality, weight and depositions were recorded and nutritional indices were calculated in no-choice tests. Results from choice tests showed a strong antifeedant effect of both extracts. In no-choice tests, the leaf and fruit extracts strongly reduced food consumption and larval weight, except with fruit extract at the lowest concentration. Larvae did not reach the pupal stage when high concentrations of leaf or fruit extract were used. Antifeedant activity was corroborated by nutritional indices, which also revealed negative effects of extracts on relative consumption, growth rates and efficiency in utilization of ingested and digested food, although digestibility was not affected. Our results suggest that M. azedarach extracts could be incorporated in management programs for this insect pest.

Keywords : Botanical insecticide; Melia azedarach; Spodoptera eridania; Antifeedant activity; Nutritional index.

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