Warty potatoes

[psa]

What causes the warts on this red Potomac?
ImageUploadedByTapatalk1348974268.803644.jpg

[wingnut]

Looks like common scab..streptomyces acidiscabies.

[Tom Wagner]

The looks of it are too uniformly distributed to me to be scab. My guess is that it is due to wet soil and is likely swollen lenticels. Once they start...secondary infections often sets in and you have a host of maladies starting. Go to this site to compare...
http://www.greenlandgarden.com/veggie_woes.htm

[Fusion_power]

Red Pontiac is also highly susceptible to nematode damage and there are a couple of nematodes that cause damage similar to the photo above. You can tell the difference by using a knife to slice the surface from one of the "warts". If there is an obvious blackened trail into the potato, then it is a nematode. Otherwise, it would probably be the lenticel problem as linked by Tom.

DarJones

[wingnut]

I stick by my diagnosis. The potato field guide to insects, diseases, and defects states "The bacterium enters newly forming tubers through immature lenticels." Swollen lenticels do not look so erumpent. But without laboratory analasis we are all just guessing. Common scab lesions often times will show mycelial growth when first dug from damp/wet soil.

[Fusion_power]

wingnut, Red Pontiac is also highly susceptible to scab. that is why I no longer grow it. There are just too many diseases and pests that attack it.

DarJones