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The versatility of the neem tree Azadirachta indica A. Juss. is reviewed. This species, native to India, grows in nutrient-poor soils in arid habitats and has tremendous potential for human use. Various derivatives of the tree have potential use in toiletries, pharmaceuticals, the manufacture of agricultural implements and furniture, cattle and poultry feeds, nitrification of soils for various agricultural crops, and pest control. Since neem is a natural renewal resource producing extensive useful biomass, its propagation and economic exploitation will be beneficial, particularly to the Third World. In recent years, some useful commercial products have been developed from A. indica, and mere is considerable scope for future product development. Potentially profitable lines of research on this plant species are suggested.

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Biological activities of the salannin type of limonoids isolated from Azadirachta indica A. Juss were assessed using the gram pod borer Helicoverpa armigera (Hubner) and the tobacco armyworm Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). Inhibition of larval growth was concomitant with reduced feeding by neonate and third instar larvae. All three compounds exhibited strong antifeedant activity in a choice leaf disc bioassay with 2.0, 2.3 and 2.8 microg/cm(2) of 3-O-acetyl salannol, salannol and salannin, respectively deterring feeding by 50% in S. litura larvae. In nutritional assays, all three compounds reduced growth and consumption when fed to larvae without any effect on efficiency of conversion of ingested food (ECI), suggesting antifeedant activity alone. No toxicity was observed nor was there any significant affect on nutritional indices following topical application, further suggesting specific action as feeding deterrents. When relative growth rates were plotted against relative consumption rates, growth efficiency of the H. armigera fed diet containing 3-O-acetyl salannol, salannol or salannin did not differ from that of starved control larvae (used as calibration curve), further confirming the specific antifeedant action of salannin type of limonoids. Where the three compounds were co-administered, no enhancement in activity was observed. Non-azadirachtin limonoids having structural similarities and explicitly similar modes of action, like feeding deterrence in the present case, have no potentiating effect in any combination.

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This paper presents an overview of the potential role of semiochemicals in integrated pest management strategies, including monitoring, trapping and mating disruption, and provide some examples of successes. It identifies the constraints and future prospects for mating disruption, and discusses efforts on the practical and commercial use of various mating disruption technologies in plant protection.

Foliar and twig extracts of three species of Aglaia were screened for larval growth inhibiting and antifeedant effects against the polyphagous lepidopteran larvae of Spodopteru lituru and Helicoverpa armigera. A . elaeagnoidea and A. odorata crude ethanolic extracts were at par in their activity at an initial treatment level of 5 mg/g of dry diet weight, while A . roxburghiana was half as active as the other two species. Detailed investigation of A . elaeagnoidea species revealed the presence of complex limonoid fractions responsible for this activity. The nutritional analyses showed impaired diet consumption and dietary utilization at 200 ppm level of treatment when limonoid fractions Fr,J and Fr,K were provided orally to S. litura larvae, indicating centrally mediated anorexic effect. The isolation of the limonoid complex from A. elueagnoidea should provide useful starting point for the development of a botanical anti-insect preparation.