Host plant influence on different subspecies of Myzus persicae (Sulzer) and de generalist aphid parasitoid Praon volucre (Hallday)

Abstract

15 p.The green peach aphid Myzus persicae (Sulzer) is a polyphagous pest with different host ranges. Myzus persicae sensu stricto is a very polyphagous aphid, while Myzus persicae nicotianae is a subspecies more specialised on tobacco. In this work we evaluated the effect of two crops, pepper and tobacco, on the intrinsic rate of natural increase (rm) of both subspecies of M.persicae. Similarly, we evaluated the effect of host plants, pepper and tobacco, on the development time,secondary sex ratio and adult dry weight of the generalist parasitoid Praon volucre (Haliday),which is the main natural enemy of this aphid species. The pepper was a suitable host for the development of both races of M. persicae, while tobacco did not allow the development of M.persicae sensu stricto. However, the rm of M. persicae nicotianae, on tobacco, was significantly lower than the rm of both races, when developed on pepper. The total development time of the parasitoid males developed on M. persicae sensu stricto - pepper was significantly higher than when they were grown on M. persicae nicotianae either on pepper or tobacco. Egg to mummy and mummy to adult development time, adult dry mass, pupal survival, as well as secondary sex ratio, did not show significant differences between host plants for both parasitoid sexes. Our results support that there are no main tritrophic interactions in this study system and the parasitoid reacts neutrally to the host plant species or aphid subspecies studied. Key-words: Myzus persicae, Praon volucre, tobacco, pepper, tritrophic effects