Predatory Potential of Episyrphus balteatus (De Geer), an Effective Predator of Lipaphis erysimi (Kaltenbach)

Predatory potential of aphidophagous syrphid fly, Episyrphus balteatus (De Geer) (Diptera:Syrphidae) against Lipaphis erysimi (Kaltenbach) was studied under laboratory conditions. The first instar larvae of E. balteatus were less voracious than older instars. The voracity (no. of aphid consumed/24 hr) of E. balteatus increased with succeeding instars. The third instar larva of E. balteatus consumed 120.2 apterous adults of L. erysimi in 24 hrs and during its entire third instar, it consumed 499.24 apterous adults. The theoretical effectiveness was worked out as 84.57, which was the product of multiplication of its seasonal average numbers in the field by its average daily consumption, which showed its potential for use as an effective biocontrol agent against mustard aphid.