Time-specific life tables for the pea aphid,Acyrthosiphon pisum (Harris), on alfalfa

摘要: Time-specific life tables were constructed for three pea aphid,Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), populations using a modification ofHughes' analytical procedure. All studied on second-growth alfalfa (mid-June to mid-July) in south central Wisconsin; data two collected during 1980, and the third population 1982. The intrinsic rate of increase (rm) estimated physiological time (day-degree) scale under field conditions but absence natural enemies, provided reliable estimate potential growth was used preference toHughes' approach estimating rates directly from stage structure data. Emigration by adult alatae fungal disease major sources ofA. mortality each studied. These factors most important because their impact reducing birth within local population. Parasitism never greater than 9 percent. Mortality attributable predation ranged 0.0 about 30.0%; however, even at highest predator densitiesA. increased exponentially.