Gnats and fan leaf problems

I have fungus gnats for more than 6 months. Sometimes I win, and sometimes they get out of control.
Recently, my yellow traps are empty. I've been using imidacloprid, rotated with Gnatrol WDG for a while.
Now I have this strange leaf problem. Leaf margins stay green but leafs are yellowing starting from the base, and die.
Midlle and lower leafs only. I flushed the pots checked my runoff and all seemed fine.

Runoff ph 5.8-6.0 , 300 ppm, no visible salt build up ,no larvae. Ambient temps are around 28 to 30 C.
Girls are in pure coco, rinsed several times before potting up.
After the flush I gave them 1/2 strenght nutes @ ph 5.6. No improvment for 10 days and progressing.

What would You suggest me to do ?

Dude... Mix one part hydrogen peroxide with 4 parts water and water it with that. And try to get one of those hot shot gnat and fly kiillers. The ones that stand up and let off fumes. Oh and it helps to put sand on top or add more soil on top after the water.

The peroxide nd the water will kill the gnats and their eggs. Also try to get rid of the main source of the gnats.

Hey SativaLion, thanks for Your suggestions. Im using airpots and topping with sand will not help.
Im also familiar with h202 and been using it the stuff at 1ml/L (food grade %35). Then I stopped using it since I started to gnatrol.
However my gnat infestation level is 1 out of 10 now. I checked the roots while transplanting and they were also fine.
Still I just cannot solve the yellowing. I do know that they can cause all kind of defiencies , but not them this time.
Maybe a post trauma that caused by the earlier damage , but this thing is spreading while there are no damn gnats.

Add crab meal to your mix. Or lobster shells. These contain chitin. This will attract benes that love to eat chitin. Gnats jaws contain chitin. The benes eat the jaws out of the gnats. Problem solved organically. This works so well. I never see gnats. One every now and then. My friend Rrog taught me this here on RIU.

Here is a great thread to learn tricks like this.

https://www.rollitup.org/michigan-patients/583341-so-who-here-growing-true.html

Picture of the whole plant would help more than just the single leaf.

Other than that, all I really have to add is DO NOT USE HOT SHOT NO PEST STRIPS, EVER. These things contain and emit quite a toxic compound (Dichlorvos) which is an acetylcholinesterase inhibitor. Packaging explicitly states that they are for use in "non-living" areas, such as dumpsters, and should not be used where people or pets actually reside.

Stick with the Gnatrol and try adding chitin as GG suggested for the gnats. Gnatrol is Bti which is a natural bacterium (also found in mosquito dunks). If you keep using the Gnatrol even while you don't see any gnats it should prevent them from coming back.

Imidacloprid is also more toxic a compound than is necessary for fungus gnats.

Thanks for the info and link GandalfdaGreen. That's something new for me.

I found this link about it and will have a deeper investigation.

I agree to keep the chems and poisons to a minimum and be careful with the hot shots.; When i have used the hot shots, it is only for 3-4 days, and only at dark when things are shut down, and it does the trick 100 percent, then I put them away for next time.

It has a half life of around 3 days (if memory serves) does not absorb into plant matter and resudues rinse off with clean water.

They have used it for decades in most every curing facility for tobacco (Now there is arousing health endorsement) and food warehouses tend to prefer using it because it IS effective and compared to everything else effective, has the least amount of time it sticks around and doesn't absorb into product.

Many of you have full strength Dicholorvis if you have cats, as it is what flea collars are still often made out of.. If you put a flea collar around the stem of your plant, you almost NEVER will have anything crawl up or around it..

Farmers use it to protect edible crops daily in this country..

Now NONE of that means anything.. we live in a poison world.. but if you use the hot shots for a few days and put them away, there are TONS of worse things people could use (acceptable things) on their plants that are worse..

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That said, gnats are easy, I wouldn't use something like Dichlorvis when simple non toxic attractants work well..

While I don't use Dichhlorivs anymore (h202 and a little red wine works wonders), if I felt it was detrimental so I didn't lose a crop, I'd use it without too much hesitation.. beats spraying shit on em for example)..

Just one guys thoughts.. they mean nothing..

Nullis, I've had to use imidaclopride or loose the plants. They were small clones with a few roots only. Thanks for the advice on pest strips as well.
Ill be posting more pics the whole plants soon.

Zoltan44x said:

Nillis, I've had to use imidaclopride or loose the plants. They were small clones with a few roots only. Thanks for the advice on pest strips as well.
Ill be posting more pics the whole plants soon.

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Nullis is an amzing source of info. I would listen to what he says. I bet it if you looked into organics, and a soil that you can use over and over all the while getting better results every run, you will eliminate any of the gnat issues from this point forward. It just takes a little planning and you will never look back. It is so much cheaper in the long run too. Take care.

Pyrethrin is my insecticide of choice for spray-on application, including during bloom. Pyrethrins break down very rapidly (< 24 hours) and they are harmless to most pets. Often it comes mixed with piperonyl butoxide which makes the pyrethrins more effective. However, products containing PBO shouldn't be used around pregnant women especially during the third trimester. It will kill adult fungus gnats and spider mites (all stages with repeated applications).

If I had to use anything use besides Dr. Bronners Peppermint soap it would be a full neem oil or perhaps even limonene.

For soil dwelling pests, I'd rather let my Hypoaspis mites go after them.

i use cedar chips on top of the plant base.. get a big bag from wallyworld. and spread it on the tops of your pots.. like the sand idea.. you can water right over top the chips and also put a few cups or pot sitting out in your room. helps with all kinds of pest and smells great too..

you might try Gnatrol WDG its organic and wont hurt you or your plants. you can get it online at Amazon. Its fairly cheap