Population Parameters and Probing Behavior of Cowpea Aphid (Homoptera: Aphididae), on Preferred and Non-Preferred Host Cover Crops

Abstract

Developmental time, fecundity, nymphal mortality, generation time, intrinsic and finite rates of increase, and time for population to double were compared for cowpea aphid, Aphis craccivora Koch, reared on cover crop seedlings of sesbania, Sesbania exaltata (Rafinesque-Schmaltz) Cory; cowpea, Vigna unguiculata [L.] Walpers; hairy indigo, Indigofera hirsuta L.; hairy vetch, Vicia villosa Roth; crimson clover, Trifolium incarnatum L.; and cereal rye, Secale cereale L. The study was conducted under near-ambient temperatures in a greenhouse from late January to mid-April. Developmental, pre-reproductive, and generation times of A. craccivora were the shortest on V. unguiculata, followed by S. exaltata and I hirsuta. However, mean total fecundity, fecundity rate, and intrinsic and finite rates of increase were higher on V. unguiculata and I. hirsuta than on the other species. No differences in life parameters were detected when A. craccivora developed on the same plant species at different evaluation periods. Probing behavior of individual A. craccivora differed on various cover crops. Mean probe duration was longer on V. unguiculata and I. hirsuta, but time to start the first probe, number of probes per access period, and non-probing duration were shorter than on other plant species evaluated.