A reader sent us a simple question a little while ago – “is this wireworms?” – in connection with a video that depicts small white worms crawling out of potatoes soaking in water. These small white worms could be wireworms (or “wire worms,” as some have it), but they could also be potato tuberworms, which are also called “tobacco splitworms” (or more precisely Phthorimaea operculella). To call the worms “small” doesn’t quite capture their size; they are more like tiny white worms, only a few millimeters long and very skinny. This can’t really be seen, but the profanity-infused narration of the video indicates that the tiny white worms are actually coming out of the potatoes, evidently only after they were placed in water. From what we can tell, the worms coming out of the potatoes look more like potato tuberworms than wireworms, but we touch on both possibilities below.
As we said, the video that shows the small white worms isn’t particularly clear, and the person narrating it is cussing up a blue streak, so we took this screenshot to give you an idea of what was found:
In this image (and basically the entire video), there is bad glare because the potatoes are under some sort of plastic wrap. Thus, the white pattern is not the worms, which can instead be found right above the glare, as well below and to the right of the glare. (There are only two in this picture.) This image shows about a square inch of the potato, so the worms are, as noted above, very small.
Although wireworms are closely associated with potatoes – if they are known at all, they are known as pests of potatoes – the creatures in the image above do not really look like wireworms, which tend to be brown or tan and quite a bit larger. However, we don’t want to definitely rule out wireworms because there are so many different species. “Wireworms” is a fairly generic term that refers to the larval form of click beetles, of which there are thousands of species. (This means wireworms are actually not worms.) Thus, to say our reader didn’t find wireworms is to rule out around ten thousand possibilities, some of which are smaller and of a lighter color, and that is something that we can’t do.
That said, the creatures in the picture above do look more like potato tuberworms, which are sometimes called “tobacco splitworm.” Like wireworms, potato tuberworms are actually not worms. Rather, they are the larval form of Potato tuber moths, which makes them caterpillars. (They start to look more like caterpillars as they grow larger.) Potato tuberworms generally aren’t quite so small, and they can also be non-white colors, but overall the creatures pictured above look more like tuberworms than wireworms. To check for yourself, Washington State University’s Mount Vernon Research Center, which serves “the agricultural, horticultural, and natural resource science interests of the state,” has a nice picture of a potato tuberworm on their site, which you can compare to their image of a wireworm.
So, we think it is more likely that our reader is dealing with potato tuberworms and not wireworms, but it is wise not to rule out either possibility. They are both common potato pests, and our reader might have found either.
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