Spatiotemporal Genetic Structure of Myzus persicae Population in Central Chile: The Role of Cultivated and Non-Cultivated Hosts

The green peach aphid, M. persicae (Sulzer), is one of the most important pests of horticultural crops worldwide. In Chile, M. persicae causes severe losses in peach and herbaceous crops. Understanding aphid population dynamics across its primary (peach) and secondary (weed) hosts is fundamental to developing a more effective pest control strategy. To investigate the spatial genetic connectivity of M. persicae populations between cultivated and non-cultivated hosts, we conducted a longitudinal survey in three commercial peach orchards in central Chile. Apterous aphid colonies were repeatedly sampled from peach trees and weed hosts located both within and outside orchards, and population genetic structure and clonal diversity were characterized using six polymorphic microsatellite loci. Genetic differentiation was low between weed populations inside and outside orchards, whereas greater differentiation was observed between peach trees and weeds outside orchards. Three recurrent multilocus genotypes persisted across multiple seasons, orchards, and host plants, indicating substantial spatiotemporal persistence of particular clonal lineages. Comparison with insecticide-resistance profiles further showed that neutral population structure and resistance-associated variation were not necessarily concordant. These findings support an important role for non-cultivated hosts in maintaining recurrent M. persicae lineages within peach agroecosystems and highlight the value of considering surrounding vegetation in integrated pest management.