Extension > Garden > Diagnose a problem > What's wrong with my plant? > Vegetable > Potato >No Emergence
Potato > Seedling > No Emergence
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Fusarium Dry Rot
Fusarium sp.
- Plant may not emerge, or may emerge small and weak
- Tuber surface has sunken dark spots, eventually becoming wrinkled in concentric rings
- In storage, tuber develops a dry decayed cavity often with white fluffy fungal growth or pink to yellow spores inside
- More information on Fusarium Dry Rot
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Blackleg and Soft Rot
Pectobacterium carotovora
- Seed potato may rot in the soil, plants do not emerge
- In severe cases, plant is stunted, with yellow and wilted leaves
- Brown to black slimy sunken lesions on stems, most common starting at the soil line
- Tuber flesh is white, soft and rotted. In severe cases the entire tuber rots away, leaving on the skin
- Favored by cool wet weather
- More information on Blackleg and Soft Rot
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Black Scurf/Rhizoctonia Canker
Rhizoctonia solani
- Stem has a white to gray flaky growth just above the soil line.
- Underground stems and roots have brown, sunken dry spots
- Late or no emergence, have few stems, and poor growth
- Small hard black spots stick to the skin of the tuber like dirt that won't wash off
- Tuber production is low, tubers may be small and deformed
- In severe cases, small green tubers form on the stem above ground
- Most problematic in cool wet soils
- More information on Black Scurf/Rhizoctonia Canker
