Summary Table
The following table summarizes the symptoms of the four major wilts -- Erwinia, Fusarium, Rhizoctonia, and Verticillium. This is an outline of the rough descriptions for identifying the wilts, stem canker and black scurf caused by Rhizoctonia solani, wilt and dry rot caused by Fusarium spp., early dying and vascular discoloration caused by Verticillium dahliae, and black leg and bacterial soft rot caused by Erwinia carotovora. The blights, early and late, are not included here.
| Vine Symptoms | ||||
|---|---|---|---|---|
| Rhizoctonia stem canker | Fusarium wilt | Verticillium wilt | Erwinia black leg | |
| vine & stem | rectangular patches | rosette wilt | one side wilts first | hollow and black stem |
| stem decay | from outer skin to inside | from ring to outside and inside | from ring to oustide and inside | from the center to outside |
| stolon | blotches pinching | slow growth | slow growth on one side | black areas pinching |
| vascular ring | discolors with decay | discolors in stem | discolors on one side | decay slimy |
| other | roots prune delayed stand emergence | leaf yellow and die all over vine | leaf yellow and die on one side first | stunted delayed stand emergence |
| Tuber symptoms | ||||
| Rhizoctonia black scurf | Fusarium dry rot | Verticillium discolor | Erwinia soft rot | |
| tuber core | none | dry cavity | none | soft, wet cavity |
| vascular ring | none | discolor and decay | discolor | discolor and rot |
| tuber surface | black spots unwashable | dry decay in wounds | discolor near eyes | sweating and decay |