Tons of tiny black flies

I’m growing organic with earthboxes and have tons of tiny black flies. Rice shaped but even tinier than a grain of rice. They are not fungus gnats and I’ve inspected my plants for a few weeks and no damage anywhere so they aren’t hurting them. I have no idea what they are though n have em flying all over my room every time I open tent. Any ideas what they could be? I put up sticky traps and they a just covered with em but didn’t seem to slow problem.

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Pics would help, but they are more than likely in the soil. You can you use Mosquito Bits for the soil. Captain Jacks Dead Bug Brew Concentrate mixed at 1.5x strength will get the airborne.

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You pour it on the soil? Not sure what you meant about getting airborne. I can try n get a pic for ya, buy they so tiny it’ll probably look like a black blur if you zoom in

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It sounds like fungus gnats to me. @Lacewing thoughts?

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Oh I didn’t realize that was just Spinosad. I already have that. I’ve sprayed on foliage before to kill pests that were on leaves.

Fungus gnats walk run or hop more than fly and kinda look like mosquitoes. These are flying all over and look different. There may be multiple types though and I’m no expert on fungus gnats, but what I said is true about them in general as far as I know


Here’s one they landed on my monitor.

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Interesting. Lacewing is our resident bug expert, hopefully he’ll get eyes on this soon. May have some ideas

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Negative. Mix with water in a spray bottle. You can spray CJDBJ on the plant at all stages of growth. Highly recommend a bud wash at harvest.

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I fight gnats with these 2 products



I put the Bits into a cloth bag crushed and let it soak in my water. Then I pour into the soil liberally.

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If there aren’t attacking my plant or eating my leaves , how does spraying on the plant help? I’m sure I’m must be missing something here

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Ya I wonder what they are. I’m glad I don’t have any plant pests at least! :smiley: I’ve had aphids n mites and a few leaf miners too, so I’ll take flies over leaf damage any day!

That’s how I started using mosquito bits. Kept the population down but they never disappeared. This grow I put a layer of them on top of the coco, applied DE generously and covered it all with a layer of synthetic black sand. Haven’t seen a gnat in my tent for weeks.

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I dont have a single gnat. They all got married off and busy making babies right now. Probably under my soil.

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You could add hydrogen peroxide to the soil… It will kill then break down into oxygen.

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If they aren’t fungus gnats …what else could they be ? I’ve had soils outdoors loaded with them and they never harmed my plant but they have other places to go …inside not so much …the amount you are talking about is very consistent with fungus gnats .they always cover the sticky traps because they are so numerous

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I think borderryan was suggesting diffy methods depending on what you find out ID’ing them.
:face_with_monocle:
Any larvae in soil? I had tiny white ones, along with my tiny black flies. Tiny, thinner than any wiggly I’ve ever seen. Now I look up gnats and more convinced I just had fruit flies.

I don’t see you mentioning what stage of growth the girls are in? If your in flower, I wouldn’t spray anything on the plants. Just don’t do it for numerous reasons.

Instead, use predatory nematodes and more yellow sticky traps. The nematodes will take care of any insect that spends all or part of it’s life cycle in the soil. The sticky traps will get the airborne adults. Should take a week to see most of not all insects gone.

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Those look like dark wing fungus knats.
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The mosquito dunks work, but I humbly suggest getting the liquid BTi instead. It is concentrated so you can do a root drench without guessing the dose like dunks. Especially if you have a few pots or a big pile of old soil. If you run living soil you will see this foe again.

Knats often don’t damage the plants obviously at first. The adults don’t hurt a thing. It’s the larvae of the knats that are a problem. They are a small worm that burrows in the soil. Almost like an eyebrow hair. They are almost too small to see. The larvae are the ones that do the damage eating root ends on all the fine roots. The larvae prefer dead organic matter so if you soil is loaded with composted stuff they go to town on that first. Hence the plants seem fine.

But eventually they eat thru the dead matter and turn on the next low hanging fruit. Those smaller root ends. I would say many plants grow thru knats ok. But it is like running a marathon with anemia. You are not going to get your best time even if you finish.

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Oh I didn’t know that. Went through 3 sticky traps already. I have plenty more so I’ll just do that then