Andrew Plant has shared final results. The Maine Seed Potato Certification’s 2020 Post Harvest Test was completed in January. This marks the third crop in which the test was completed entirely in its Disease Testing Laboratory. In the laboratory, ELISA is used to serologically test sprout sap to provide infection level estimates for PVY and PLRV.
Virus testing results from the 2020 crop were a strong improvement from 2019. Several factors likely contributed to this including improved virus management, lower aphid populations, and a decreased and delayed volunteer potato inoculum load. Below are some statistics to highlight the results. Individual seed lot results can be found in the 2020-2021 Post Harvest Test Book
- Rejection rate (>5% virus) decreased from 7.31% of tested acres in 2019 to 3.19% of tested acres in 2020
- Foundation (<0.55% virus) increased from 44.5% to 63.4% of seed acres.
- 10-fold decrease in tested lots with virus levels greater than 10%, from 2019 to 2020.
- Total Harvested Inoculum Level decrease from 1.83% PVY to 0.94% PVY.
- Certified Seed Inoculum level for planting decreased from 1.06% PVY for the 2020 planting, to 0.70% PVY for our upcoming 2021 planting season.