Resistance breakdown has been observed following the deployment of plant cultivars resistant to pests. Assessing the durability of a resistance requires long-term experiments at least at a regional scale. We collected such data for melon resistance conferred by the Vat gene cluster to melon aphids. We examined landscape-level populations of Aphis gossypii collected in 2004–2015, from melon-producing regions with and without the deployment of Vat resistance and with different climates. We conducted demo-genetic analyses of the aphid populations on Vat and non-Vat plants during the cropping seasons. The Vat resistance decreased the density of aphid populations in all areas and changed the genetic structure and composition of these populations. Two bottlenecks were identified in the dynamics of adapted clones, due to the low levels of production of dispersal morphs and winter extinction. Our results suggest that (i) Vat resistance will not be durable in the Lesser Antilles, where no bottleneck affected the dynamics of adapted clones, (ii) Vat resistance will be durable in south-west France, where both bottlenecks affected the dynamics of adapted clones and (iii) Vat resistance will be less durable in south-east France, where only one of the two bottlenecks was observed.

Genetic data_Spring migrants Aphis gossypii on melon cropsAphis gossypii spring migrants- collected during the 3 weeks following transplantation- on melon crops in France. MLG= MultiLocus Genotype based on 8 SSR markersGenetic data_Wingless Aphis gossypii on melon cropsDemographic data_Aphis gossypii on melon cropsMLG Aphis gossypii_Allelic composition at 8 SRRSize of Amplification product at each locus. 999 = missing data