Oberon46 said:I also have smart pots which I emptied each fall. And I got potato scab the first year. Then stupidly planted in the same bags the next year with the same results. Duh. I decided to sell them as I wasn't impressed with the harvest after several years of trying different soil and amendments. I put them in the washing machine with bleach. Clogged up the machine and had water all over the floor. DH was really grumpy. 
I should at least have beaten the bags out a bit to looses dirt. Anyway, I don't now if that cured the blight or not as haven't used them again. I have 4-5 of the super 18" 20 gallon ones with handles and 8 16" with no handles. Maybe next year I will give it another go. I know people who get wonderful harvests from them and can't figure out why I can't. Wrong mix or need fertilizer during the summer maybe??
Potato scab
Treatment
All of the following control measures have been proven to be effective. However, in most cases a combination of techniques will be required.
Plant certified, disease-free seed potatoes and resistant varieties whenever possible. We suggest using the russet-skinned varieties, since they have more resistance to the disease.
Rotate root crops by planting in alternate locations to limit this disease.
Potato scab is most prevalent in dry, alkaline soils. Decrease soil pH by adding elemental sulfur. The disease is controlled or greatly suppressed at soil pH levels of 5.2 or lower. Simple and affordable soil test kits are available to check pH often.
Tilling in a cover crop prior to planting potatoes will help reduce infection by S. scabies.
Keeping soil moist during early tuber development may have a dramatic effect on common scab infection. Maintain proper soil moisture for about 2 weeks after the plants emerge from the soil. Avoid overwatering.
