Nectariless Cotton: Effect on Growth, Survival, and Fecundity of Lygus Bugs1

Abstract

Experiments were conducted in the laboratory, greenhouse, and field to evaluate the effect of the nectariless character in cotton, Gossypium hirsutum L., on growth, survival, oviposition rate, and population increase of lygus hugs, Lygus hesperus Knight. Survival of L. hesperus nymphs on Stoneville 7A nectariless was 16% lower than on ‘Stoneville 7A’ during a 7‐day growth period. Reduction on other nectariless lines was not as great. Survival of female L. hesperus, confined for 14 days on a nectariless cotton, was 6% less and the number of nymphs emerging was 12% less than on the nectaried commercial standard, ‘Acala SJ‐I.’ Growth rates of lygus populations, during two generations in field cages, were reduced 34% by the nectariless character in Acala H4016 nectariless and 40% on Stoneville 7A nectariless when compared to their nearisogenic nectaried commercial standards. Populations of lygus bugs on Deltapine 16 nectariless were not lower, however, than on its nectaried near‐isoline. Thus, the response of the insect was affected not only by the nectariless character but also by the genetic backgrounds of the cultivars and lines tested.