Bioefficacy of Neem and Mahogany Extracts for Control of Cowpea Flower Thrips, Megalurothrips sjostedti Trybom [Thysanoptera: Thripidae] and Grasshopper, Ailopus simulatrix Walker [Orthoptera: Pyrgomorphidae] in Sudan Savanna, Nigeria

Neem (Azadirachta indica A. Juss.) and mahogany (Khaya senegalensis Desr.) extracts were tested on two insect pests namely the grasshopper, Aiolopus simulatrix Walker(Orthoptera: Acrididae), and the flower thrips, Megalurothrips sjostedti Trybom (Thysanoptera: Thripidae). Number of leaves and flowers of cowpea (Vigna unguiculata) (L.) Walp damaged by thrips and grasshoppers were quantified during the rainy seasons of 2010 and 2011 at the Dry Land Teaching and Research Farm of Usmanu Danfodiyo University Sokoto. Plots were laid cd in a randomized complete block design, replicated three times. Treatments consisted of 5 % and 10 % extracts of neem seeds, 10% and 20 % extracts of each of neem and mahogany leaves., synthetic pesticide (Karate 1 l/ha) and untreated control. Results showed that plant extracts conferred significantly (P<0.05) better control of pests than the untreated control. Significant reduction (P<0.05) of thrips and grasshopper populations on flowers and leaves of cowpea plants respectively, were obtained after spraying with neem and mahogany extracts. Neem seed extracts competed favourably with the synthetic insecticide (Karate), while the untreated control suffered more insect pest attack.