Potato > Tuber > Tuber skin discolored
1 of 4
- Potato exposed to light turns a pale green color
- Potato tastes bitter
- Excessively green potatoes are poisonous
- More information on Greening...
2 of 4
- Round rough, brown spots on tuber surface
- Spots may be slightly raised and rough or slightly sunken depending on cultivar
- Disease only affects tubers
- Disease is favored by alkaline and dry soils
- More information on Common Scab...
3 of 4
Black Scurf/Rhizoctonia Canker
- Small hard black spots stick to the skin of the tuber like dirt that won't wash off
- Delayed or no emergence, have few stems, and poor growth
- Underground stems and roots have brown, sunken dry spots
- Tuber production is low, tubers may be small and deformed
- In severe cases, small green tubers form on the stem above ground
- 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...
4 of 4
- Brown to gray leathery patches form on tubers
- Tuber has a silvery, metallic sheen on the surface when wet
- Only the tuber skin is affected
- More noticeable on red-skinned varieties
- More information on Silver Scurf...