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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Vegetable > Potato > Tuber growths on stem

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Potato > Stem > Tuber growths on stem

1 of 2
  • Black Scurf/Rhizoctonia Canker 1
  • Black Scurf/Rhizoctonia Canker 2
  • Black Scurf/Rhizoctonia Canker 3

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...
2 of 2
  • Zebra Chip 1
  • Zebra Chip 2
  • Zebra Chip 3

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...

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