What is God trying to tell me through this potato?
July 26, 2011 6:01 PM

Why do my potatoes have stigmata?

So I've been growing potatoes in my garden for quite a few years. After reading Michael Pollen's book, Botany of Desire, I almost feel obligated to do it, in spite of the fact that there's not a lot of ROI in the endeavor. And because they're so cheap, I don't know a lot of other people who do it, and thus find something of a void of information about the practice. This year, I came across something new. Not all, but quite a few of my potatoes had dark patches that seeped a dark red fluid. Here's a pic.

So I did some poking around and I don't find any obvious diseases. There's nothing I could find below the surface of the skin so if it's an infestation, they are microscopic organisms. I suspect some form of fusarium, but that's just what I'm getting from the Google. Anyone else ever come across this?

Worth noting, these are clones from commercial potatoes. In spring, about when it's time to put potatoes in the ground, any you have in the house exposed to natural light cycles will start to bud in the eyes are perfect for cutting up and throwing in the ground. So that's what I do typically and did this year. The varieties were your run of the mill russet and white potato. This infection seemed to affect the russets more than the whites, but both seemed afflicted, but only about 30% of the harvest for the russets, maybe 10% of the whites. Do you know what caused this?

Other possibly relevant factors—the myth of global warming seems to have expedited this years harvest of almost everything. Things seem more mature this year at this point than they have in the past. We had a pretty early last frost, about three weeks before typical. Also, the potatoes grew next to garlic and some of the plants were likely volunteers from last years crop.
posted by Toekneesan to Home & Garden (10 answers total) 2 users marked this as a favorite
I'm sorry I don't have a response to your tater stigmata inquiry, but I was wondering - where are you located? In the U.S., crops of everything from corn to almonds to cranberries are notoriously delayed this year due to a cool, wet spring.
posted by keasby at 6:12 PM on July 26, 2011


Central Pennsylvania.
posted by Toekneesan at 6:13 PM on July 26, 2011


And I think the delay in commercial crops this year had more to do with the rain than the temps. Farm equipment hates mud. But rain ain't a good reason to wait putting in your graden. It's more like a reason to do it.
posted by Toekneesan at 6:17 PM on July 26, 2011


Potato diseases of Pennsylvania.
posted by empath at 6:20 PM on July 26, 2011


Potato diseases of Pennsylvania.

I looked at that. Do you see it in there?
posted by Toekneesan at 6:33 PM on July 26, 2011


What do the potatoes look like when you cut into them?
posted by MonkeyToes at 6:36 PM on July 26, 2011


There's the slightest bit of darkness near the surface around the sores and dark patches. But I dug and squinted and found nothing I could see.
posted by Toekneesan at 6:41 PM on July 26, 2011


How do you feel about potato scab?
posted by mudpuppie at 9:29 PM on July 26, 2011


Naturally I'm against it, but its the seeping that seems unique to my potatoes and not mentioned in descriptions of potato scab that I've come across. It seems a lot of the typical diseases in the PSU pamphlet linked above create lesions and discoloration on the skin, but the seeping I'm not finding reference to. I don't know if you can tell by my picture but it's actually bubbling, like some kind of fermentation may be going on just below the surface.
posted by Toekneesan at 2:11 AM on July 27, 2011


From empath's link--check out the section on powdery scab. (More here and here.) The mention of pimples, pustules and cankers seems closest to what your photo shows.
posted by MonkeyToes at 3:09 PM on July 27, 2011


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