Reproductive parameters of a new biocontrol agent, Eupeodes americanus (Diptera: Syrphidae) and comparison with the commercialized Aphidoletes aphidimyza (Diptera: Cecidomyiidae).

Abstract

The American hoverfly Eupeodes americanus (Wiedemann) (Diptera: Syrphidae) is an aphidophagous predator during its larval stage and is currently being evaluated for inclusion in biocontrol programs as a new biocontrol agent. However, little is known about its reproductive aptitudes. The objective of the present study was to determine the reproductive parameters of E. americanus and to compare them with those of a commercialized and widely used biological control agent for aphids, the aphid midge Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae). The preoviposition period, oviposition period, adult longevity, lifetime and daily fecundity, egg hatching rate, and fertility were determined for E. americanus females and compared to those of A. aphidimyza. Trials were conducted under laboratory conditions in rearing cages on the broad bean plant Vicia faba L. (Fabaceae), infested with pea aphids Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae). The results revealed that the preoviposition period, oviposition period, and adult longevity were significantly longer in E. americanus than in A. aphidimyza. The daily fecundity and egg-hatching rate were similar in both species. However, lifetime fecundity and fertility were considerably higher in E. americanus than in A. aphidimyza. This study demonstrates that the reproductive capacity of E. americanus is clearly superior to that of A. aphidimyza and therefore supports its inclusion in the aphid pest management program as a new biocontrol agent.