RESUMO
The performance of eighteen clones of Myzus persicae (Sulzer) on pepper and tobacco plants at 20 degrees C and L16:D8 and the choice of young adult apterae between tobacco and pepper leaf-discs were examined. The clones were collected from weeds and peach in two tobacco-growing regions: Katerini, northern Greece and Karditsa, central Greece (only from weeds) and from Lehonia, central eastern Greece where tobacco is not cultivated. All clones did well on both hosts. However, the analysis of data revealed a significant effect of "region / host plant origin" on aphid performance. The mean values of adult weight, intrinsic rate of increase and fecundity of the clones collected in Lehonia and reared on tobacco were significantly lower than the observed values for clones from Katerini and Karditsa. Aphids from Lehonia had significantly higher mean values for developmental time on tobacco than clones from the other regions whereas the opposite was observed when aphids were reared on pepper. Aphids collected in Lehonia performed better on pepper than those originating from the tobacco-growing regions. A choice test revealed differences among the clones originating from different regions. Fifty three percent and 43% of aphids from weeds and peach from Lehonia, respectively, chose pepper. By comparison 41.5% and 40.0% of aphids from peach and weeds from Katerini, respectively and 49.5% of aphids from Karditsa preferred tobacco. The results are discussed in relation to host specialization in M. persicae.
