What are these worms and are they destroying my tubers?

West Caldwell, NJ(Zone 6b)

We haven't had a lot of rain, but I have had many small stunted distorted dahlias, many took an extra 2-3 weeks to come up and they are tiny and unhealthy. Some never came up. So the last two days I have dug up the no-shows. Most were just stringy husks, others were full of gelatinous goo. Those with the goo often contained the tiny white worms I am showing in the picture. What are these awful things? Are they doing this? Or are they just scavengers eating already rotten tubers? I had many tubers looking like husks last year, but I thought it was rot from the rain, there has been almost none, and for two weeks I had them covered with row covers keeping them dry.

Thumbnail by todgor
West Caldwell, NJ(Zone 6b)

Well, I think I answered my own question, they do seem to be cabbage root maggots, or at least some kind of root maggot (develops into fly). I found a picture of a pupae, and I did find something exactly like that. And the adult cabbage root flies are probably one of two or three kinds of flies intensely interested in my dahlias as long as I can remember. They seem very difficult to control. I bought more nematodes specifically mentioning them, next year I will probably start all my tubers in pots, maybe use the extra light row covers I found at Gardens Alive to keep the flies from laying eggs at the plant bases. Though this year I found row covers get in the way. Its very irritating... :(

south of Grand Rapid, MI(Zone 5a)

well that just plain stinks...

(Arlene) Southold, NY(Zone 7a)

So very sorry to read your posts, Tod. Nature can certainly be cruel at times.

Shenandoah Valley, VA

Tod, if you'll post a list of what varieties you lost, I'm sure those of us who have gotten dahlias from you would be happy to save tubers for you to help you replace them.

Calgary, AB(Zone 3a)

O that is so frustrating Todd. So sorry for your loss :(

West Caldwell, NJ(Zone 6b)

Thanks everyone for the kind thoughts, I am potting up all the intact tubers with sprouts and/or leaves that are looking the worst, I have a bunch of extra tubers on hand but its kind of late to start them. All is not lost, I have a bunch growing and will see how they do. I like to save my debugging for computers, not plants. :)

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