*Center of Plant Protection, Department of Agriculture, Tehran University, Tehran, Iran
**Department of Entomology, Islamic Azad University, Tehran, Iran
Online published on 23 July, 2015.
The identification of potentially attractive flowers as food sources for hoverflies is an important tool for a good management of ecosystems and conservation of natural enemies. The objective of this study was to test the effect of five non-crop plant species – Anchusa azurea Mill, and Echium plantagineum L. (Boraginaceae), Hirschfeldia incana (L.) Lagr.-Foss. (Brassicaceae), Hypericum perforatum L. (Hypericaceae) and Malva sylvestris L. (Malvaceae) – on longevity and nutrient status of Episyrphus balteatus (Diptera: Syrphidae). In this study, M. sylvestris and A. azurea had a positive effect on longevity and life expectancy of E.balteatus. This study confirms hoverflies can have a strong impact on aphid numbers, but only when sufficient floral resources are available. It also shows that this impact even extends to cabbage aphids. Hoverflies are potential agents in conservation biological control because of their intimate relations with flowers and aphids, with the larvae of many species being predators of aphids while adults feed on nectar and pollen. Thus, conservation or implementation of this species in the field may promote E. balteatus lifespan and thereby, its impact as a biological control agent against pests. And also Cage experiments show that when suitable flowers are present the hoverflies can strongly suppress the growth of cabbage aphid colonies on Brussels sprouts.
