Grocery stores have set up their seed potato displays, and many
gardeners are getting ready to plant. However, some have
expressed dismay about last year's crop: disfigured, dark,
rough, pitted and corky, their potatoes were infected with
potato scab, a disease caused by a soil borne bacteria. Potato
scab bacteria lives on organic material in the soil and infects
young tubers through pores or wounds. The infection produces
reddish-brown spots that grow into large corky lesions. Spores
develop in these lesions and are shed into the soil, just
waiting to do more damage next year. Infected potatoes that are
used as seed potatoes the following year can re-infest the soil
where they are planted. Although potatoes infected by potato
scab are unsightly, the tubers are edible, and the scabby areas
can be peeled away. If stored in dark, cool, dry locations, the
potatoes keep reasonably well. There are no chemical controls
recommended for home gardeners, but there are some cultural
practices that will help to control t