Bacterial ring rot—Clavibacter michiganensis
pv. sepedonicus
In some potato varieties bunchy or rosetted terminal leaves may appear on young plants. Terminals appear
darker green than the rest of the plant. Foliar symptoms of bacterial ring rot generally appear at midseason
or later. Yellow areas develop on leaf margins or between veins and later turn brown, giving the leaves
a burned appearance. The leaflet margin rolls up and becomes necrotic. Plants with advanced symptoms show
vascular discoloration and milky, viscous bacteria may be forced from cut stems. In tubers the rot begins
as a brown necrosis in the vascular ring and progresses to the surface. Cracks may appear on surfaces
of tubers, which are frequently nothing more than hollow shells.
Life cycle
Solutions
Use only certified
seed tubers, rotate out of potatoes for at least 1 year, and follow strict sanitation
procedures when cutting seed. Periodically disinfect cutting tools in a 1% solution of calcium hypochlorite. |
Yellowing and burning of foliage |
|
Ring
rot in tuber
|
Cracks
on surface
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