Potato Virus Y (PVY) levels in the New Brunswick potato industry have dropped dramatically in the last decade following the instituting of strict regulatory limits on PVY in seed lots and through careful in-field management by growers of this aphid-spread disease, Potatoes New Brunswick says in a news release.
Average PVY level in all tested potato seed lots harvested in 2009 was 11.8 per cent — a decade later in 2019 it had dropped to 0.63 per cent. This is close to the lowest level ever measured in the N.B. potato industry, which was 0.43 per cent in 2016.
While the PVY level in seed lots has dropped dramatically, so to has the the number of seed lots rejected due to PVY level exceeding the provincially-mandated virus cap. Currently, the cap is 4 per cent, harvested lots testing higher than this cannot be sold as potato seed in N.B. As of last year 98.1 per cent of seed lots were below this threshold for rejection, near the record performance of the 2016 crop at 98.4 per cent.
A limited resurgence of PVY was found in seed potato lots in 2017-18. However, this may have been tied to a rise in the aphid populations. During those years, average PVY in all tested lots briefly rose above one per cent, before dropping again in 2019. This small resurgence caused an increased rejection of N.B. seed lots for those years, resulting in an estimated loss of $2 million in seed sales.
The research findings on the drop was led by Mathuresh Singh and Tyler MacKenzie of Potatoes New Brunswick’s Agricultural Certification Services lab in Fredericton N.B. MacKenzie presented the findings at the N.B. Potato Conference and Tradeshow on Feb. 6.