Antifeedant effects of the limonoids from Entandrophragma candolei (Meliaceae) on the gram pod borer, Helicoverpa armigera (Lepidoptera: Noctuidae).

The biological activity of the limonoids prieurianin and epoxyprieurianin isolated from Entandrophragma candolei (Harms) (Meliaceae) and their respective acetates was assessed using the gram pod borer, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae). The compounds exhibited strong antifeedant activity in a diet choice bioassay with epoxyprieurianin acetate being most effective with 48.3 ppm deterring feeding by 50% (DI50) and prieurianin the least effective (DI50 = 91.

6beta-hydroxygedunin from Azadirachta indica. Its potentiation effects with some non-azadirachtin limonoids in neem against lepidopteran larvae.

The biological activity of 6beta-hydroxygedunin isolated from Azadirachta indica A. Juss. was assessed using the gram pod borer, Helicoverpa armigera (Hubner), and Asian armyworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), alone and in combination with other limonoids, gedunin, salannin, nimbinene, and azadirachtin.