Interaction between aphid resistant cowpea cultivars, three clones of cowpea aphid, and the effect of two light intensity regimes on this interaction

The performance and probing behaviour of three cowpea aphid clones were studied on four cowpea cultivars reared under bright and poor light conditions. The cowpea cultivars included two resistant (TVu 801, TVu 3000), a semi‐resistant (TVu 36) and a susceptible cv. (Ife Brown). The general trends under the two light conditions were similar: a Nigerian clone off groundnut had the poorest performance, producing no offspring, even off Ife Brown; a Philippines clone performed well on all cultivars, with high mean relative growth rates and fecundity, while a Nigerian clone off cowpea performed well on Ife Brown and TVu 36 but very poorly on the resistant cultivars, particularly under bright light conditions. Almost all aphid performance parameters were significantly improved on plants grown under low light, particularly with the Philippines clone. It was concluded that (a) some clones do not readily transfer from groundnut to cowpea; (b) the resistance in TVu 801 and TVu 3000 appeared to be effective a...