Rotting Potatoes

Asked July 26, 2018, 3:00 PM EDT

Pontiac Red Potatoes that were brought into our Extension office. They were grown in a small garden. The gentleman planted one row of these potatoes, one end of the row look like the pictures I have attached and the other end the potatoes are perfect. He did have some Potato Beetles on them and has been using Seven Dust to control them. He said the same thing happened last year. Looking through books at the office makes me think, its the larvae from the Beetles or bacterial rot. But, I'm no expert. Could you please guide me in the right direction. Thank you!

Gladwin County Michigan potatoes beetle larva

1 Response

That looks like more than one issue. I suggest the gardener dig up potatoes earlier next year to determine the initial cause.

Deep pitting and raised bumps such as these, can be caused by Common Scab.

The raised lenticels can be from too much water.

The overall softness could be from initial scab infections becoming a full-on rot due to excess moisture.

Common scab is controlled or greatly suppressed at soil pH levels of 5.2 or lower. However, not many other vegetables like it that low.

Here is a good resource about Common Scab: http://msue.anr.msu.edu/resources/potato_diseases_common_scab_of_potato_e2990