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Twenty-two advanced breeding genotypes of cowpea were evaluated for their responses to infestation by the cowpea aphid, Aphis craccivora Koch. The aim of the study was to identify genotype(s) of cowpea resistant to A. craccivora to be used as breeding line(s). Seedling screening technique and aphid growth and reproduction on each genotype were used to classify the genotypes into resistant and susceptible groups. The cowpea genotypes SARC 1-57-2 and SARC 1-91-1 were found to be the most resistant genotypes, whereas five of the genotypes namely, Apagbaala, IT 97K-499-35, IT 98K-506-1, IT 95K-193-2 and Marfo-Tuya were highly susceptible. The high susceptibility of the IITA lines must be a cause for concern, particularly the IT 97K-499-35 line which is known to be resistant to A. craccivora in Nigeria. This suggests the existence of cowpea aphid biotype in northern Ghana which is more virulent than the biotypes in Nigeria. The results support earlier findings of the development of aphid biotypes that are more aggressive and are not controlled by the aphid resistance varieties of cowpea developed by IITA for Nigeria. pests and diseases (Montimore et al., 1997; Blade et al., 1997). Cowpea is one crop which suffers serious insect pests infestation from the time of planting through harvesting and during storage (Obeng-Ofori, 2007). Cowpea aphid, Aphis craccivora Koch (Homoptera: Aphididae) is a major insect pest of cowpea in Africa, Asia and the Americas (Obeng-Ofori, 2007). Singh and Allen (1980) estimated yield losses of 20% to 40% in cowpea due to A. craccivora infestation in Asia and up to 35% in Africa. The existence of alternative host plants during the crop-free season, intermittent dry periods during the rainy season and favourable tem

Seeds of five different landrace cultivars of Kersting's groundnut, Macrotyloma geocarpum (Harms) Marechal and Baudet, obtained from northern Ghana, were evaluated for their susceptibility to infestation and damage by the pulse beetle, Callosobruchus maculatus Fab. The completely randomized design was used to obtain data on the oviposition, developmental period, progeny emergence, weight loss in seeds and susceptibility index. The results showed that the Nakpanduri-white, Heng-mottle and Damongo-cream landrace cultivars proved to be the highly preferred hosts to C. maculatus, recording the highest egg load and progeny emergence, as well as the shortest egg-adult developmental period, and highest seed weight loss. The Najung-black landrace cultivar was the least preferred, followed by the Nakori-brown cultivars. Results from susceptibility indices further indicated that the Najung-black and Nakori-brown were the least susceptible to C. maculatus, while Nakpanduri-white was the most susceptible. Overall, the Najung-black and Nakori-brown landrace cultivars consistently demonstrated high tolerance to the pest and therefore, should be promoted or incorporated into breeding programmes to help minimize the high losses incurred by farmers during storage.

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Field studies were conducted at the Experimental Farm of the Savanna Agricultural Research Institute (SARI), Nyankpala, northern Ghana, during the 2006 cropping season to evaluate the effect of aqueous neem (Azadirachta indica A. Juss) seed extract at 5, 10, 15 and 20 per cent on Aphis craccivora Koch., Megalurothrips Original scientific paper.