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Are these Fungus Gnats?
- Thread starter chimei
- Start date
Thanks. I would never grow in pots again without doing this. Worked in soil and has worked just as well when I switched to coir. It might look like a pain in the ass, but once I cut the screens and bought the pea gravel it's been simple. I use two pot sizes and do this to both. Veg and flower covered. After harvest I pour the gravel into a bucket and wash it and wash the screens. Both last forever. Much more effective than repeated treatments with anything. Gnatrol works well, but is expensive, has a limited shelf life and literally smells like shit. Actually tossed half a canister in the trash the other day, since I haven't need it since implementing this system.
I've moved to DTW coir for both veg and flower. The gravel and mesh help distribute the feeding over the surface and help slow drying of the top layer.
Thanks for the confirmation!
Looks like I will just order 1 lb of it. Probably more shelf stable then this liquid microbelift.
Even though I have not had these issues in the past, I think I will use it moving forward as a preventive after I get past this, and keep the sticky traps around as part of my routine to help monitor. I don't ever want to deal with this again at this level.
So last week I got some medium grade white sand and hit them with another dose of microbelift then shortly after put around .5 - 1 inch of the white sand over the tops of the plants, That seemed to have the greatest impact so far. I put out a new sticky trap right outside where the plants are located (the gnats seem to like exploring) and for the next few days only like 1 or 2 were caught each 24 hours. Then at like days 5-7 more seemed to get caught each 24 hours. Still only like 20% of the activity I was seeing before this. I also noticed each day when the lights would come on, there would be like 5-10 hanging out sitting on the sand. (I would spray those with SM90 to kill them) I am guessing because they are stupid and don't know where to go, and that the ones currently being born are coming from the bottom of the pots. Each day there were more, so I have to assume they are coming out the bottom of the pot.
So I got some Gnatrol and today I am doing the same thing, first I vacuumed all the white sand out, then watered with Gnatrol and will put new sand back on them all and see what happens. Hoping the Gnatrol is like a nuke now for those remaining.
So I got some Gnatrol and today I am doing the same thing, first I vacuumed all the white sand out, then watered with Gnatrol and will put new sand back on them all and see what happens. Hoping the Gnatrol is like a nuke now for those remaining.
Yes, I saw that. Unfortunately I am in sorta in a balancing act at this point. Not sure if it is from root damage from those bastards, or keeping my soil too moist while continuously trying to kill them with the different methods I have tried so far. Usually at this point I am at they want to drink ever 2 days. This last watering was almost 6 full days after, which means they are not drinking like they usually should be at this stage.. and if it were not for the gnats, I probably would have waited another 2 days to water them. They are bordering nute lockout I think now. I think they did too much damage in the beginning, I just did not realize it.
I am going to keep those sticky things up in the future and the 1st one will start treating with this Gnatrol. Never want to go through this again.
Wanted to update my post. I still wonder if these were fungus gnats. I kept hitting them every 3 days with that Gnatrol mixed in at 1TB per gallon. And put an inch of white sand on top of each pot, never killed them all off. The #'s were down, but always still more were on the sticky traps and I would still have flyers.. Did that up until they were finished then tossed the dirt. I did an experiment, I took some of the dirt (around 2 gallons worth) tossed it into a 5 gallon bucket - no noticeable air born flyers at this point, dumped some mosquito bits and watered with gnatrol to moisten the dirt (not too moist) put the lid on the bucket and after like 3 weeks opened the container and there were like 50 of them flying around. Tossed that dirt also.
All I have now is like 2 clones in small cups and a sticky trap in their box, the damn things are still around. These clones are filled with sand at the top of the cups, and I have them sitting in two cups the same size so when I water them with gnatrol, it sits in the liquid for a good day before it soaks into the inner cup that contains the clone. So there is no way those larva would not be completely killed I would think. I can pick the inner cup up and there will be flyers inside the cup that must emerge from the holes in the bottom of the clone cups when I would check before the next watering time. Either these are not fungus gnats or their larva is immune to the chemicals. I am going to take cuttings and throw these 2 clones out, bought new dirt that was kept in the sealed bag in another area. I never see them emerge from the sand at the top of the cups, but they have to be. There is 0 source for these left, other than these 2 clones. I don't see flyers in any other room of our place.
These things were a nightmare!
One other thought I had, even though I dislike the idea of no pest strips, if I just sit a no pest strip in the box with the 2 clones for like a week, anyone think that would be dangerous and in the plant if they are then vegged and put into flowering a few months later? I don't want to make plant matter that contains toxic chemicals. But technically it would be months till they were done, so I am not sure if that would be OK. If I just exposed the clones to a no pest strip for like a week or two.
All I have now is like 2 clones in small cups and a sticky trap in their box, the damn things are still around. These clones are filled with sand at the top of the cups, and I have them sitting in two cups the same size so when I water them with gnatrol, it sits in the liquid for a good day before it soaks into the inner cup that contains the clone. So there is no way those larva would not be completely killed I would think. I can pick the inner cup up and there will be flyers inside the cup that must emerge from the holes in the bottom of the clone cups when I would check before the next watering time. Either these are not fungus gnats or their larva is immune to the chemicals. I am going to take cuttings and throw these 2 clones out, bought new dirt that was kept in the sealed bag in another area. I never see them emerge from the sand at the top of the cups, but they have to be. There is 0 source for these left, other than these 2 clones. I don't see flyers in any other room of our place.
These things were a nightmare!
One other thought I had, even though I dislike the idea of no pest strips, if I just sit a no pest strip in the box with the 2 clones for like a week, anyone think that would be dangerous and in the plant if they are then vegged and put into flowering a few months later? I don't want to make plant matter that contains toxic chemicals. But technically it would be months till they were done, so I am not sure if that would be OK. If I just exposed the clones to a no pest strip for like a week or two.
BMC will eradicate them in a heartbeat. 6 drops treats a 100 gallons of water, so the stuff goes a long way. Just mix it in with your nutrients or water and continue watering with it till you dont see them anymore.
https://www.amazon.com/Ecological-Labs-AEL20036-Mosquito-Treatment/dp/B007UTE55A
https://www.amazon.com/Ecological-Labs-AEL20036-Mosquito-Treatment/dp/B007UTE55A
Chimei those are gnats 100% bro. Some are resistant to BT I tried to warn you before. I've seen university studies on it so no matter what product you use it's not going to work. I tried them all with zero effect..
Sand on top is not going to help if you don't block them from coming in thru the bottom. Sand is not going to help if you are using the wrong kind of sand. You need quartz sand aka sharp sand aka pool filter sand.
A cup in a cup isn't going to work either. There is enough space for them to climb thru the gap between the 2 cups. I tried it too, it doesn't work.
You're better off taking a fine needle and making a bunch of tiny drain holes with that. Or put your cup in a womens knee high panty hose sock to cover the drain hole. $0.50 a pair at Walmart. This works well but you need to swap out the sock out or wash it every week because the larvae will live on the outside of it if there is any moisture at all on the bottom from runoff when watering.
It's a pita but you got a small grow so it really shouldn't be that much of a pita for you.
Sand on top is not going to help if you don't block them from coming in thru the bottom. Sand is not going to help if you are using the wrong kind of sand. You need quartz sand aka sharp sand aka pool filter sand.
A cup in a cup isn't going to work either. There is enough space for them to climb thru the gap between the 2 cups. I tried it too, it doesn't work.
You're better off taking a fine needle and making a bunch of tiny drain holes with that. Or put your cup in a womens knee high panty hose sock to cover the drain hole. $0.50 a pair at Walmart. This works well but you need to swap out the sock out or wash it every week because the larvae will live on the outside of it if there is any moisture at all on the bottom from runoff when watering.
It's a pita but you got a small grow so it really shouldn't be that much of a pita for you.
Use cinnamon grounded and dust you soil.. this will kill much faster gnat larvae than
Bti... its tryed in real life.. am knocked some serious gnat infestations just with
cinnamon and yellow sticky traps...
cinnamon for larvae,yellow sticky trap for flyers.. and its cheap method..
Bti... its tryed in real life.. am knocked some serious gnat infestations just with
cinnamon and yellow sticky traps...
cinnamon for larvae,yellow sticky trap for flyers.. and its cheap method..
Yeah, I was optimistic at first the #'s did decrease overall I guess. And the sand seems to work from the top side, I have not seen any activity on the top. I do think the ones I got here are immune, they have made it through numerous "soaks" with gnatrol.
I like your idea about panty hose or tiny pin holes in the cups. Am going to try re-potting into cups with pinholes. Before I resort to just taking clones or no pest strips. Thanks for that. Maybe I can still "win". haha
Interesting.. Next time I will try that. (hope to NOT have a next time though) Since the entry point or where they are thriving seems to be the bottom of my clone cups at this point, I don't know if I can do that. Maybe might try soaking some cinnamon in the water for a day before I water to see if that helps at all.
Mosquito Bits, Gnatrol, microbe lift, hydrogen peroxide, neem oil. None of these I tried seemed to kill off all the larva. Not enough to break the cycle.
I already tried this, did not break the cycle.
Gnatrol has the same ingredient as this stuff but at a MUCH higher level.
Maybe the fungus gnats I have are slightly more hardy then usual, I don't know.
I like this thread because people are acknowledging that sometimes what we thought as being the perfect cure doesn't always work for everybody. My last bouts with gnats resulted in pouring several different products into my soil that had little apparent effect, even though they'd been successful previously. Can't say why. I do have some very old plumbing that appears to be a ready reservoir of gnats though.
This isn't a cure, but sometimes it's nice to just knock the population down a few notches. You describe your gnats as being active around the bottom drain holes of your containers. If you let the soil dry out some it will drive the larvae to the bottom in search of a moist environment. You can take advantage of this behavior.
Let your plant containers soil dry out to drive larvae downward. Get a bottle of some pyrethrin based natural insect killer such as Garden Safe brand Houseplant & Garden Insect Killer. Dilute this pesticide with around 2 or 3x that amount with water. Then fill a pan with a half inch of this solution and set a plant container in the pan to soak up the solution from the bottom. Do this for each plant. It won't eliminate your gnats but it will immediately and significantly cut back the next generation. If you have beneficial critters you want to keep, this may not be best, but everything in life is a trade off.
Having a treefrog living in your grow room is great for control of adult gnats.
This isn't a cure, but sometimes it's nice to just knock the population down a few notches. You describe your gnats as being active around the bottom drain holes of your containers. If you let the soil dry out some it will drive the larvae to the bottom in search of a moist environment. You can take advantage of this behavior.
Let your plant containers soil dry out to drive larvae downward. Get a bottle of some pyrethrin based natural insect killer such as Garden Safe brand Houseplant & Garden Insect Killer. Dilute this pesticide with around 2 or 3x that amount with water. Then fill a pan with a half inch of this solution and set a plant container in the pan to soak up the solution from the bottom. Do this for each plant. It won't eliminate your gnats but it will immediately and significantly cut back the next generation. If you have beneficial critters you want to keep, this may not be best, but everything in life is a trade off.
Having a treefrog living in your grow room is great for control of adult gnats.
I do like the idea of having a treefrog living in my grow area
Thanks for the tips, I did not consider that, but it makes sense. (that they would travel downward to the most hospitable environment, and because of the drainage holes it left a bunch of doors for them to come and go as they please.. Unfortunately for me I had netting and I had most sites tied down on each plant, and the containers suspended like 12+ inches above a catch pan.
So I am not sure how I could have drenched the bottom with a different type of insecticide. Moving forward I am now going to keep sticky traps in my clone area so before potting I know if any of the plants have gnats, before their population explodes. And I am going to more closely monitor incoming new dirt! I think I found out the source finally, I thought it was from dirt, but I think it actually started from a bag of earth worm castings I had mixed in with the soil back before this all started.
I do have to say after all trimming, did not find any stuck in any of the plant material. Which was what I concerned with initially the most. Because the plants did not seem to be stunted that much (had to go maybe 5 days longer), other than in the beginning when I was watering at odd intervals with no nutes because I was afraid it would make the treatments less effective.
Yeah, you must have some Chernobyl bred gnats or something because I had them pretty bad about 3-4 years ago and I got rid of them over a period of 1-2 months using BMC (2-3 drops a gallon) every single time I watered even if I didn't see them. Finally I just didn't see them anymore and haven't since.
I think the key is consistancy. You just gotta keep using it as its not a magic one time application that gets rid of them all.
Pest resistance to BT is well documented. Most extensively through Monsanto. Also through university clinical studies. I used Microbelift at up to 4x recommended dose every watering for months. Didn't even make a dent in the numbers. Before I moved to MA, BT worked like a charm. Hard for some people to believe, myself included until I got them, but the truth is there are in fact BT resistant populations of fungus gnats now.
