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What are these disgusting Marijuana Maggots?

Can someone please help me identify what insect ruined my outdoor plants this year?

Note: I’m in NE Colorado

Here’s a video of the worms (caterpillars):

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Caterpillars are bad this year. A lot of outdoor Growers are finding them.

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Below is a link with a 1000+ page document used to identify and treat diseases and pests on Canadian vegetable crops. A lot of information and treatments can be applied to cannabis. I’ve found the section on greenhouse cucumbers to be the most applicable.


This might help, but I don’t have time to sit and look. Hope this helps identify your pests.

Do you use pesticides at all?

At this time of year, after the buds begin to resin up real good, the butterflies…around my house its mostly yellow butterflies and white ones too…but they lay eggs on your buds. I’m no in depth bug person or anything, I just grew some outside and had the same thing happen to me. The bugs lay eggs on your buds that then hatch out these puppies which, in the course of a day or so, can mow down everything you’ve got in the area. It’s easy to get them on a plant and spread them to others by touching several plants in one outing after picking them up. To the best of my knowledge, using Seven Dust, a basic garden dusting powder, will keep your plants safe. You have to be sure and keep them dusted throughout their lives, especially after they begin to put on buds and accumulate resin, and you can rinse the plant at harvest to get it off. You have to reapply after rain. I know you can sprinkle it on a caterpillar and it’ll drop like a hot rock straight to the ground. We’ve used this stuff in our veggie gardens all my life and none of us have died from any strange diseases or anything, in case you have a safety of consumption question RE the dust. Nothing you can do about it now. We also got bud rot along with the caterpillars and lost the majority of several nice fat plants. Lesson learned. Our main setup is inside and we were doing a few outside just because they get so doggone beautiful…if you can get them to harvest. Sorry you had this happen. Hope this helps some.

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I got these bad this year also. I’m mainly indoor also but can’t resist 8 foot trees!!! I had a thought that I might try next year. Will hanging moth balls from plants help deter those stinkin moths from messing with my plants? Has anyone tried this!

DO NOT USE SEVIN DUST ON MJ. Carbaryl is no where near natural and WILL cause harm to human if ingested and most definitely not good to smoke.

My internets are shoddy and video res was very low. Please post a higher res picture of actual pest on this thread for better i.d.

My guess is beet armyworm or corn earworm out in the plains. Armyworm was and is bad on the western slope.

BT/ Bacillus Thuringensis powder is a great control for any caterpillar type larvae and is a bio control that is not toxic to humans.

Check out this thorough list of hemp bugs from CSU:


No Sevin Dust outdoors. No mothballs inside lol. Your herb will come out stinking and penetrated by moth balls. You could try the cedar balls or cedar oil, but same issues at least not toxic… BT will kindly kill any worm mode insects

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@BG_SAGE That a great resource. Thanks for sharing.

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BT is great and effective. They were back this season. I documented my battle with them a few weeks ago…one round of BT they were gone