Rates of Increase and Probing Behavior of Acyrthosiphon pisum (Homoptera: Aphididae) on Preferred and Nonpreferred Host Cover Crops

Abstract

Developmental time, fecundity, nymphal mortality, generation time, intrinsic and finite rates of increase, and days for population to double were compared for peaaphid, Acyrthosiphon pisum Harris, feeding on cover crop seedlings of sesbania, Sesbania exaltata (Rafinesque-Schmaltz) Cory; cowpea, Vigna unguiculata [L.] Walpers; hairy indigo, lndigofera hirsuta L.; hairy vetch, Vicia villosa Roth; crimson clover, Trifolium incarnatum L.; or cereal rye, Secale cereale L. The study was conducted under constant temperatures (15, 20, 25, and 30°e) in the laboratory. A. pisum had the shortest developmental, prereproductive, and generation times on V. villosa and T. incarnatum , followed by V. unguiculata . However, A. pisum had higher mean total fecundity, fecundity rate, and intrinsic and finite rates of increase on V. villosa and T. incarnatum than on other cover crops evaluated. Differences in life parameters of A. pisum were detected on the same plant species exposed to different temperatures. Probing behavior of individual A. pisum differed on various cover crops. Mean probe duration was longer on S. exaltata and I. hirsuta , whereas the time to start the first probe, the number of probes per 6-min observation period, and nonprobing duration were shorter on V. villosa and T. incarnatum than on other plant species evaluated.