Fungus gnats & thrips problem

[Christine20]

Hello, guys,

I m once again asking for your help regarding a infestation we don t know how to deal with. I m talking about fungus gnats and thrips.
We are growing in a hydroponic system (pebbles) and now the girls are in their late veg stage. Lately we noticed this infestation I told you about. We tried to get rid of them using a chemical insecticide and it was a bad decision, as the leaves got burnt. They are slowly recovering.

We are really looking for an organic solution in order to minimize the "bugs".

Let me know if you know some.

Thanks a lot! Cheers

[3Berries]

I use Mosquito Bits. It's BT and added to the water I use for soli. You can put it in a sock and let it soak in the water. Works very well.

[UndergroundFarmer]

A spinosad spray like Captain Jack's Dead Bug will get rid of thrips. Spraying with a solution of natural insecticidal soap like Dr. Bronner's once a week will help get rid of their eggs.

[Motoman15]

Diatomaceous earth and yellow sticky boards will solve your problem.

[DW2]

How does one apply diatomaceous earth to a hydroponic system? I have heard of applying it to the top of soil to help control the bugs.

[Blowdout2269]

I have done everything that the knowledgeable three people have shared. It will work if you're diligent. These are excellent solutions. Though I will add one thing:
I had a horrible thrip problem a couple of years ago. Went as far as using 50/50 isopropyl alcohol and water sprayed on and under leafs, stems, floors, walls...everything. Not in flower of course. It's only a contact killer, but I needed immediate results, lol. As soon as I'd think they were gone and I'd easy up, they're back with a vengeance! They were bad.
Good luck to ya!

[dilvish]

Diatomaceous earth and yellow sticky boards will solve your problem.

Yup or fly paper but definitely spread some of the DE around the room too. You can also mix it with warm water and use it as a foliar spray but leave it on for at least 24 hours then rinse it off. I use a garden sprayer that has a manual pump and it works great for applying it and rinsing it off. Got mine for about $12.99. FYI you should use "Food Grade" Diatomaceous Earth. These two options (fly paper and DE) are organic solutions that are the most beneficial to those who will end up consuming the buds!!!

[DW2]

Howdy Christine20, In my hydroponic system I have used Azamax to kill off thrips, but some folks do not like to use chemicals (even though organically derived). I do cover over the net pot and pebbles with aluminum foil (to prevent light intrusion and algal growth) and this also keeps the little critters from getting into and laying their eggs.
Good luck with your 'pets'.

[AGH]

First off, every grower eventually deals with both thrips and fungus gnats, so be proud that you can add that badge to your grow vest!

I grow organic (in soil of course) and I found that for thrips, the best I could hope for was to manage them. I used neem oil (veg only) once or twice a week. I sprayed the soil, but doing a foliar spray just before lights out would work just fine in your hydro setup. Insecticidal soap worked well too which can also be used as a foliar spary. **IF YOU DO A FOLIAR SPRAY, DO IT JUST BEFORE LIGHTS OUT TO AVOID BURNING YOUR PLANTS**

For the fungus gnats, I found that the insecticidal soap did a great job with Diatomaceous Earth dusted over the surface a day after watering as well. Obviously you don't have soil to dust so the DE won't do much for you really.

Also, make sure to have plenty of fresh air and lots of air circulation if you don't already. Neither of those pests are great flyers so if there's a breeze, it makes it difficult for them to fly around, land on your plants, get jiggy with it, or lay eggs.

Lastly, sometimes you have to accept that pest 'control' is just as efficient as pest 'eradication'. Keep an eye on your plants health and go from there. Generally, it's best to start with the gentlest, least invasive solution and go from there. If they're not hurting your plants or your buds and you don't see their numbers increasing, sometimes that's good enough. Afterall, your goal as a grower is generally fat, healthy, high yielding plants that are safe and enjoyable to consume.

A couple things to know:
1) Both of these pests (especially thrips) are tenacious. It will take a lot of consistent effort to get them under control.
2) Even if you get to the point where you don't see any live pests (larva or adult), KEEP ON DOING YOUR PEST CONTROL REGIMEN! The eggs can stay dormant for a while and if you stop too soon, they'll come right back.

Keep vigilant, be patient, and relax - everything will be okay and you'll have another learning experience in your arsenal for future grows!