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 cankerFusarium wiltVerticillium wiltErwinia 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