Agroecosystems in the tropics include growing two or more crops in diverse polycultural patterns. In Kenya, cowpea Vigna unguiculata (Walp.) is grown in combination with cereals such as maize and sorghum, perennial legumes such as pigeon peas and root crops such as cassava and sweet potatoes. In the present investigations, field experiments were conducted to study the incidence and damage caused by Clavigralla tomentoscollis Germ, and C. shadabi, after flowering, on cowpea intercropped with maize. It was evident from the present studies that C. tomentoscollis and C. shadabi were more prevalent on cowpea during the first season rather than during the second season. Both species had a preference for feeding on cowpea intercropped with maize than when it was grown in pure stands. Consequently more pod damage was recorded on cowpea planted with maize. It was therefore concluded that this agricultural system, which is commonly practised by smallscale farmers in Kenya, is undesirable from the point of view of bug damage.

No abstract

No abstract

No abstract

Two trials were conducted to study the components of yield. In one trial three genotypes were planted in three blocks with the objective of studying the dynamics of seeds/pod during seed maturation. Pods were dissected to reveal the developing seed 20 days after flowering (DAF) and at harvesting. In another trial, 14 genotypes were planted in RCBD in three contrasting environments: Bureti, Njoro and Lare with the objective of studying the components of yield. Seeds/pod was significantly different, both at 20 DAF and at harvesting. Although there were more pods at harvesting compared to 20 DAF, 3seeded pods was the mode 20 DAF while the mode was 1-seeded pod at harvesting which may be explained by seed abortion. Seeds/pod was significantly different at the three sites. Yield and its components were highest at Bureti compared with Lare. It is apparent that seeds per pod are influenced by seed abortion.

No abstract