Nymph Growth and Development, Oviposition, and Seed Damage on Cowpea by Lygus hesperus (Heteroptera: Miridae)

Abstract
Twenty cowpea genotypes were tested for resistance to Lygus hesperus Knight. During 1982, we measured the effect of these genotypes on nymph survival and growth, and ovipositional preference. Susceptibility of the 20 genotypes to Lygus-induced seed damage was also measured in both natural field and caged adult female infestations. Nymph growth and seed damage were evaluated again in 1983. Significant reductions in nymph growth were measured on 8 of the 20 entries when compared with the susceptible standard ‘California Blackeye 5’ (CB5). The two genotypes exerting greatest reduction on nymph growth were PI 170861 and PI 148674. Oviposition by Iygus bugs was significantly lower on ‘KR78-3-2’ and PI 367925 than on ‘CB5’. Mean numbers of seeds damaged by Iygus bugs were significantly lower for the cowpea acquisitions ‘New Era’, PI 227829, and ‘CR17-1-13’ than for ‘CBS’ in both free-choice and no-choice experiments. Several of these cowpea acquisitions appear to be good genetic sources for developing improved varieties with resistance to lygus bugs.