Carrot seed moth in all of my dill - Ask Extension
The larvae of this moth have been in my dill blossoms for three years now, although not so much last year. I've never seen the moths but their egg we...
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Carrot seed moth in all of my dill #876610
Asked July 10, 2024, 8:30 AM EDT
The larvae of this moth have been in my dill blossoms for three years now, although not so much last year. I've never seen the moths but their egg webs are in all my dill plants. How can I get rid of these? I've found little written about them online.
Newaygo County Michigan
Expert Response
Thank you for your question!
The most common insect pests of dill are aphids, spider mites, white flies, and thrips, all mostly sucking insects on plant stems.
I found this article on what you are reporting as purple carrot seed moth. Compare the printed picture with what's in your garden.
Non-native insect to watch: purple carrot-seed moth | UMN Extension
Saving seeds? Look out for this new non-native insect (umn.edu)
Both articles point to hand picking and insecticidal soaps as a way to control the population. Basic garden hygiene may help in your decreasing the incidence year after year.
Don't save seeds from this year's crop to grow next year and try planting your dill in another location. However, this website is where you can report this invasive species.
Reporting | National Invasive Species Information Center
It may have other tips on how to eradicate it from your garden.
The most common insect pests of dill are aphids, spider mites, white flies, and thrips, all mostly sucking insects on plant stems.
I found this article on what you are reporting as purple carrot seed moth. Compare the printed picture with what's in your garden.
Non-native insect to watch: purple carrot-seed moth | UMN Extension
Saving seeds? Look out for this new non-native insect (umn.edu)
Both articles point to hand picking and insecticidal soaps as a way to control the population. Basic garden hygiene may help in your decreasing the incidence year after year.
Don't save seeds from this year's crop to grow next year and try planting your dill in another location. However, this website is where you can report this invasive species.
Reporting | National Invasive Species Information Center
It may have other tips on how to eradicate it from your garden.
Well, I had already read the articles you mentioned. I have found that the egg-laying is not for a long period of time. I took off all of the dill flower heads that had "nests" and destroyed them. Now I look for some clustering of the flowerlets and pull them off. The worms that hatched from the eggs look exactly like the photographs on the Minnesota website. I could not determine whether spraying Neem on the flowers had any effect. There were many black flies and what appeared to be parasitic wasps on the flowers the days after I sent you my question. Now they are gone. I was not able to report the presence of this insect on the reporting site because it only gave me the opportunity of reporting some sort of citrus pest/disease.
Thank you for your response! Please give me a few days to find more information out about this situation and I will report what I find back to you.
After one whole week of spending lots of time with my dill plants I now observe that this egg-bwebbing business by the Purple corn-seed moth is not a continuous activity. I squished or drowned lots of larvae and two insects kept landing on and flying around the dill flowers (perhaps to prey on the eggs or larvae?) . One may have been a tiny wasp and the other looked like most flies. I'm hoping that the egg-laying is only a week long event. I also saw a weaker attempt at webbing in the cilantro but that was already growing seeds.
Thank you for being patient in my response as I needed to consult with experts on campus!
I had an opportunity to check with Sarah Hughson the Arthropod Diagnostician at the Plant & Pest Diagnostic Center with Michigan State University. She mentioned she couldn't diagnose without a sample sent to her. It can be done using the webpage here:
Plant & Pest Diagnostics (msu.edu)
In her response back to me she cited there is a carrotseed moth (Sitochroa palealis) and a purple carrotseed moth. Both appear to be present all over the Northeast and upper Midwest. She didn't see anything about it requiring reporting in Michigan. Carrotseed moth, purple carrotseed moth and parsnip webworm seem to have some hosts in common and some that they do not share.
Carrotseed moth: http://www.minnesotaseasons.com/Insects/carrot_seed_moth.html
I also emailed David Lowenstein who is the MSU Consumer Horticulture Educator who specializes in integrated pest management, managing invasive species, pests and pollinators.
He mentioned that it is not going to be easy to eradicate, as its larvae feed on Queen Anne's lace and carrot. Beyond plant rotation or handpicking, there’s not much to do to stop it.
I am not sure if you have some parasitic wasps or insects that are feeding on the larva? Time will tell. Good luck with all your endeavors!
I had an opportunity to check with Sarah Hughson the Arthropod Diagnostician at the Plant & Pest Diagnostic Center with Michigan State University. She mentioned she couldn't diagnose without a sample sent to her. It can be done using the webpage here:
Plant & Pest Diagnostics (msu.edu)
In her response back to me she cited there is a carrotseed moth (Sitochroa palealis) and a purple carrotseed moth. Both appear to be present all over the Northeast and upper Midwest. She didn't see anything about it requiring reporting in Michigan. Carrotseed moth, purple carrotseed moth and parsnip webworm seem to have some hosts in common and some that they do not share.
Carrotseed moth: http://www.minnesotaseasons.com/Insects/carrot_seed_moth.html
I also emailed David Lowenstein who is the MSU Consumer Horticulture Educator who specializes in integrated pest management, managing invasive species, pests and pollinators.
He mentioned that it is not going to be easy to eradicate, as its larvae feed on Queen Anne's lace and carrot. Beyond plant rotation or handpicking, there’s not much to do to stop it.
I am not sure if you have some parasitic wasps or insects that are feeding on the larva? Time will tell. Good luck with all your endeavors!
Thank you for your collection of information. I can't say that I'm happy to have the news that there are three of those "webworms" ! I have found pictures of the tiny caterpillars and those on my dill match the ones for the purple carrot-seed moth. I do have carrots but they were planted late and will likely not blossom for a few more weeks. Maybe I'll miss that one. I haven't seen any webs on the Queen Ann's lace that grows in one of my hay pastures.
Salle
Best of luck to you!
