Differential thresholds of azadirachtin for feeding deterrence and toxicity in locusts and an aphid

Conclusions The importance of using azadirachtin in the field at levels causing primary antifeedancy may have been overemphasised in the past. Currently, it is recommended that commercial preparations of neem be applied at 50–100 ppm (a.i.). While this would undoubtedly have an antifeedant effect in many phytophagous insects it may also harm beneficial species (Schmutterer, 1990). By lowering the concentration of azadirachtin applied to the crop, food intake by insect pests with low chemoreceptor sensitivity to azadirachtin, e.g. aphids (Nisbet et al., 1993; 1994), would not initially be affected. However, secondary antifeedant effects, IGR and sterilant effects could rapidly manifest themselves and bring about crop protection by reducing insect pest populations without harming natural predator or parasitoid populations.