Antifeedant activity of fruit and seed extracts of Melia azedarach and Azadirachta indica on larvae of Sesamia nonagrioides

Methanolic extracts of seeds and fruits of the chinaberry tree, Melia azeda rach L. (Meliaceae), showed strong antifeedant activity against 2nd instar larvae of Sesamia nonagrioides Lefebvre (Lepidoptera: Noctuidae), a very se rious pest of maize (Zea mays L.) in Mediterranean countries. Extracts were applied in an artificial diet at concentrations of 1000 and 2000 ppm. The parameters used to evaluate the activity were larval growth rates; quantity of food ingested; phagodepression/phagostimulation index; quantity of fras s produced; quantity of material ingested; duration of larval development; and cumulative mortality. Seed extract showed high bioactivity at both dose s, while fruit extract proved to be less active, and only at the higher dos e used (2000 ppm) did it display a slight antifeedant activity. The activit y of the M. azedarach seed extract at the higher dose (2000 ppm) was compar able to that of pure azadirachtin applied at a dose of 1.25 ppm, or to 'Mub el', a commercial extract of Azadirachta indica A. Juss. (Meliaceae), appli ed at a dose of 75 ppm.