Extension > Garden > Diagnose a problem > What's wrong with my plant? > Vegetable > Potato > Tuber growths on stem
Potato > Stem > Tuber growths on stem
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Black Scurf/Rhizoctonia Canker
Rhizoctonia solani
- In severe cases, small green tubers form on the stem above ground
- Tuber production is low, tubers may be small and deformed
- Delayed or no emergence, have few stems, and poor growth
- Underground stems and roots have brown, sunken dry spots
- Small hard black spots stick to the skin of the tuber like dirt that won't wash off
- Stem has a white to gray flaky growth just above the soil line.
- Most problematic in cool wet soils
- More information on Black Scurf/Rhizoctonia Canker
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Zebra Chip
Candidatus Liberibacter spp.
- Aerial tubers form from main stem
- Leaves may be purple or yellow, appear scorched, and wilt
- Inside of potato is a mottled brown
- Vectored by the potato psyllid
- Currently not found in MN. If suspected, report it to the Minnesota Department of Agriculture at the "Arrest the Pest" Hotline: 651-201-6684 (metro) or 1-800-545-6684 (Greater Minnesota)
- More information on Zebra Chip
