D3070: Monitoring aphid populations and potato virus Y incidence in southern Colorado

The aphid-vectored potato tuber-necrotic virus, Potato Virus Y (PVY) is an economically important threat for the potato industry and commercial potato production. The San Luis Valley (SLV) is the leading producer of potato seed in Colorado. The environment and location of the SLV elicits heavy aphid infestations and the spread of PVY. Other principal crops grown in the SLV are alternatives hosts for aphids, including alfalfa, hemp, quinoa, and other vegetable crops. These crops may serve as reservoirs for PVY and incubators for generating novel and "rare" recombinants of the virus. To further understand the relationship between aphid populations and the change in PVY incidence and strains, potato leaf tissue was collected throughout the 2021 growing season (between May and September). Several years (since 2017) of aphid monitoring data indicate that peak aphid flights in the SLV occur at the end of July and the beginning of August. Therefore, strain analysis was performed on the later samples, to increase the chances of finding new recombinant strains. In nature, PVY currently exists as a complex of strains and variants that have been characterized and named based on their geographical origin and biological, serological, and molecular properties. There are five non-recombinant genotypes, thirty-six unique recombinant structures between two or more parental lineages have been reported. Our data suggests that the trends in PVY strain are changing and the increase in incidence of PVY throughout a growing season, coincides with aphid flight—further suggesting aphids could be allowing novel recombinant PVY strains.