Population genetic structure of the aphid pest Myzus persicae in organic and conventional greenhouses

Aphids display remarkable adaptability to pest control strategies and their partheno-genetic reproduction results in rapid numerical increase of higher-fitness clones. Con-sequently, a high prevalence of only a few clonal lines could indicate positive selection for these genotypes, potentially reflecting adaptation to pest control methods. Here, we investigated the clonal diversity and population genetic structure of the green peach aphid Myzus persicae using microsatellite markers, in both organic and conventionally managed Dutch sweet pepper greenhouses over four consecutive years. In total, 26 distinct multilocus genotypes (MLG) were detected, with higher clonal diversity in organic than in conventional greenhouses. Strikingly, a single MLG dominated conventional greenhouses in 2019, only to be completely replaced by a new dominant MLG by 2022. Whole-genome sequencing of 15 sampled lines — seven sharing the same MLG and eighth with unique MLGs — revealed that all aphids with the dominant MLG of 2019, collected from various locations and over multiple years, originated from a single parthenogenetic ancestor. Our findings indicate that the population genetic structure of M. persicae differs between organically and conventionally managed sweet pepper greenhouses. The presence of dominant MLGs in conventional crop systems may suggest positive selection or evolutionary forces such as a founder effect. Understanding the forces driving these differences in population genetic structure and their impact on the efficacy of biocontrol agents will further help us improve control strategies for M. persicae in greenhouse crops.