Colorado Seed Potato Growers to Adopt New Testing Rule
The mandate for direct tuber testing takes effect in 2027, requiring growers to change how they screen for potato virus.
Updated on Oct. 31, 2026 in Agriculture
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Colorado seed potato growers will face a new direct tuber testing regulation starting in 2027 to lower Potato Virus Y levels. The industry is currently wrapping up post-harvest virus testing in Hawaii for the 2026 harvest cycle.
Why it matters
Seed potato growers must strictly manage virus transmission to ensure compliance with a 25% virus limit for saved seed. Implementing direct tuber testing on dormant varieties offers a more precise method to identify and mitigate viral spread before the next planting season.
Commercial seed saved for planting in Colorado must meet a 25% virus standard to remain certified. While previous management focused on vine desiccation, the new testing framework will officially take effect in 2027.
The players
Colorado Potato Certification Service
An regulatory body responsible for verifying seed potato health and enforcing virus standards for Colorado growers.
The details
Direct Tuber Testing allows for the screening of dormant potato tubers like Canela Russet and Waneta for Potato Virus Y. This complements existing vine desiccation practices used between July and August to limit aphid-borne virus spread. By testing dormant tubers directly rather than relying solely on post-harvest grow-outs, growers gain a more immediate and accurate assessment of virus levels within their seed stock.
Timeline
Late July 2026 to mid-August 2026: Growers desiccated potato vines to limit aphid activity.
Fall 2026: The main seed potato harvest occurred across the San Luis Valley.
December 2026: Post-harvest virus testing takes place in Hawaii.
Before Christmas 2026: Growers will receive preliminary virus test results.
2027: The new direct tuber testing regulation takes effect.
Market Landscape
The introduction of direct tuber testing updates the compliance protocols set by the Colorado Potato Certification Service. This shift represents a transition toward more intensive diagnostic screening to meet long-standing industry virus thresholds.
Growers should prepare for new diagnostic requirements by reviewing their dormant seed varieties like Canela Russet and Waneta. Operators should align their 2027 seed selection processes with the incoming testing mandate to ensure their inventory remains under the 25% virus limit.
The takeaway
Direct tuber testing provides a significant operational shift in how seed health is validated before spring planting. Growers should monitor their preliminary test results expected before Christmas 2026 to identify potential virus trends early in their specific seed lots.
Further reading
For more on industry standards and production updates, explore Colorado agriculture.
Source note: This article includes information reported by The Valley Courier.
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