Predatory potential and developmental ability of aphidophagous larvae of Episyrphus balteatus (De Geer) (Diptera: Syrphidae) in relation to variable aphid – host plant combinations in Eastern Uttar Pradesh, India

Abstract

Aphids inflict a great damage to agricultural and horticultural crops by sucking their sap and transmitting viral diseases in them. Biological control of aphids is safe and effective if judiciously applied. Among the natural enemies of aphids, aphidophagous larvae of hover flies are considered as significant natural enemies of aphids. The larvae of E. balteatus are generalist predator and feed on many aphid species infesting various host plants. Here 11 food complexes composed of three aphid species and their host plants were tested to assess the feeding potential of the predatory larvae and the effect of food complex on life-cycle parameters and adult longevity in order to ascertain the most suitable prey aphid-host plant combination. Though significant differences were recorded in feeding potential (in terms of mean prey consumption per day and mean prey consumption during the entire larval period), larval, pupal and total postembryonic duration when the larvae were provided with different food complexes, but all of them attained adulthood with no larval or pupal mortality. The pupal weight and adult longevity displayed significant differences among the tested food complexes and adult longevity showed a positive correlation with the pupal weight. Thus, it can be concluded that the aphidophagous larvae of hover fly E. balteatus have great potential to be utilized as bio-control managers of these aphids in agro-ecosystems as they can equally exploit all the three tested aphid species which subsisted upon various host plants and can be regarded as suitable diet combinations for them.