ABSTRACT

The antifeedent effect of aqueous extracts of neem (Azadirachta indica A. Juss) leaves was assayed using an abundant and potentially pestiferous grasshopper (Orthoptera: Acrididae) of Indian grasslands, Oxya velox F. A neem extract of 0.00004% (40 mg powdered leaves in 1-l water) applied to the food plants of 4^th instar nymphs decreased daily consumption of the grasshoppers by 22% (a significant reduction compared to untreated controls) and caused a significant (6 d) reduction in longevity, relative to individuals fed on untreated foliage. An extract of 0.00006% (60 mg in 1-l water) decreased daily consumption of the grasshoppers by 50% (a significant reduction compared to untreated controls and 0.00004% extract) and significantly reduced (12 d) their longevity, relative to individuals fed on untreated foliage. At the highest neem concentration of 0.0001% (100 mg in 1-l water), daily consumption was reduced by 77% (a significant reduction compared to untreated controls and lower concentrations of extract) and significantly reduced (20 d) their longevity, relative to individuals fed on untreated foliage. Thus, it appears that simple, water-based extractions of neem may provide substantial protection of treated foliage from damage by grasshoppers.

grasshopper, phytophagy, consumption, pest management

¹Accepted for publication 6 January 2000.
²Department of Zoology and Environmental Sciences, Gurukul Kangri University, Hardwar-249,404 India (currently BOYSCAST Fellow at the University of Wyoming).
³Corresponding author: Association for Applied Acridology International and Entomology Section, Department of Renewable Resounces, University of Wyoming, Laramine, Wyoming 82071-3354.