Antifeedant effect of neem, Azadirachta indica A. Juss., kernel extracts on Kraussaria angulifera (Krauss) (Orthoptera: Acrididae), a Sahelian grasshopper

Abstract

The neem tree, Azadirachta indica A. Juss., is now grown extensively throughout the Sahel. Neem kernel extract (NKE) appears to offer the possibility of being a readily available and easily prepared crop protectant for use by subsistence fanners. NKE was tested in Niger against the grasshopper, Kraussaria angulifera (Krauss), a univoltine species of economic importance on grain sorghum and pearl millet. In field cage experiments using sorghum seedlings, aqueous NKE, prepared on site, was as effective as a USDA-prepared ethanol extract of Indian origin. For 72 h post-treatment, the feeding injury sustained by neem-sprayed seedlings was not significantly different from that sustained by Cymbush/Cygon-sprayed seedlings. Neem appeared to be more effective against nymphs than against adults. In feeding-choice experiments with nymphs, neem-sprayed seedlings sustained significantly less feeding injury than did nonsprayed seedlings for 144 h post-treatment.