Toxic effect of citrus peel constituents on Anastrepha fraterculus Wiedemann and Ceratitis capitata Wiedemannimmature stages

Abstract

The toxicity of essential oils from the citrus peel has been proposed as the major resistance mechanism offered by citrus to fruit fly infestation. We evaluated the insecticidal activity of the ether extracts from the lemon (Citrus limon [L.] Burm.) and grapefruit (C. paradisi Macfadyen) peel as well as from limonene and citral against Anastrepha f raterculus (Wiedemann) and Ceratitis capitata (Wiedemann) immature stages. We also evaluated the toxicity of the extracts at two ripening stages. Extracts proved toxic to A. f raterculus egg and larvae. The lemon and grapefruit extracts showed the same toxicity in both fruit fly species. For A. f raterculus eggs, citral was more toxic than limonene; for larvae, they showed equal toxicity. Anastrepha f raterculus eggs were more sensitive than C. capitata eggs. In conclusion, we provide evidence of chemical resistance mechanisms that could account for the nonhost condition of lemon for A. f raterculus.