Identification of Generalist and Specialist Phenotypes of the Peach-Potato Aphid Myzus persicae (Insecta : Hemiptera : Aphididae) in Agroecosystem of Northeast India

Different phenotypes of the peach-potato aphid, Myzus persicae, with prominent differences in ecological and biological performances were identified on mustard, eggplants and potato plants in the agroecosystem of Tripura, north east India. Asexual clones of M. persicae on mustard plants were consistently light green in colour and their adults were heavier than the greenish yellow to light pink coloured aphids of this species that occurred on eggplants and potato plants in the same geographical area. Life history traits, like population growth rate, carrying capacity of respective plants, mean relative growth rate, intrinsic rate of increase and net reproductive rates differed between the three plant species. Differences in life history traits persisted in reciprocal host plant transfer experiments; aphid clones from mustard plants when transferred to eggplants and potato plants did not survive but those from the latter two plant species survived and colonized well on mustard plants. Results showed that M. persicae in the agro-ecosystem of Tripura consisted of at least two distinct phenotypes, the 'specialist' phenotypes from mustard plants and the 'generalist' phenotypes from eggplants and potato plants. These results may have significant implications for designing crop-specific measures for the management of M. persicae.