Cause An aphid-transmitted virus, potato virus Y, when combined with potato virus X.
Symptoms Little mottling is present, but leaves are decidedly wrinkled and curled. Individual necrotic spots start and progress until the leaf dies. Lower leaves die first; sometimes leaving a stem with a tuft of wrinkled leaves at the tip.
Cultural control
- Use certified seed potatoes.
- Rogue out infected plants.
- Control aphids. See PNW Insect Management Handbook for details.
- Avoid cultivating after potato plants are tall enough to hit the tool bar.