Neutral genetic variability and resistance mechanisms present in Myzus persicae (Hemiptera: Aphididae) from different hosts in central Chile

Myzus persicae is considered the third pest of economic importance in Chile affecting several crops. Its genetic variability is influenced by the availability of the primary host. M. persicae has acquired resistance to most of the insecticides used for its control. The current work aimed to evaluate the genetic diversity and the presence of resistance mechanisms of M. persicae in crops, such as peach and sweet pepper. The study was carried out in twelve localities, six in the O'Higgins region and six in the Maule region of central Chile. Monthly collections were performed on the crops and their associated weeds. To evaluate the neutral genetic diversity, seven microsatellite markers were used, and the identification of mechanisms was performed by allelic discrimination tests. According to the results, the highest genetic diversity (> 0.80 on average) was found in peach populations. In sweet pepper and associated weeds, this diversity was 0.36 on average. The frequency of individuals with resistance mechanisms was low and predominantly heterozygous in the hosts assessed, suggesting that the sexual reproduction form of the aphid influences the levels of resistance to the insecticide. The presence of resistance mechanisms in M. persicae depends on the host, the geographical region, and the time in which they are evaluated. There is sufficient evidence that the populations of M. persicae are comprised of extremely few genetic groups, presenting different resistance dynamics to insecticides in the same agricultural season.