I currently used nematodes at my grow for fungus gnats and was wondering if anyone has had any luck with them before? Pros, and cons?
best for fungus gnats. literally nothing else works.
will take some time if youre in an outbreak but if you start using bti all the time and nematodes when you have an outbreak (you can use both together) you should be good. I just went thru a gnarly fungus gnat situation. used AzaMax, gnartrol, gnat nix, yellow stickies (I still use), neem, h2o2, some other chemical that was supposed to work, nothing worked. h2o2 did the best of any but biological is the solution for sure
Glad you found something that works! What variety are you using and where do you get them?
Absolutely! We had water gnats (black gnats) and they cleared them right up. Though we used them conjunction with predatory inspects Stratiolaelaps scimitus. It was just a two or three days until we didn’t see anymore gnats.
The yellow stickies are the most underrated fungus gnat control, cheap and effective, and they also let you ‘measure’ population by counting the squares.
@roosul Nematodes are a necessity for compliant control imo. https://buildasoil.com/collections/beneficial-insects/products/beneficial-insect-combo-packs-large?variant=12411696382069
BaS does a phenomenal job of ensuring live products arrive to you in the fastest way possible.
Thanks for all the helpful information.
I have tried the yellow stickies they work great but yes they only tell you how bad the problem is.
We also tries the strato mites but unfortunately didn’t have too much luck. But thanks for the helpful insight.
BTI works best but it only kills the larvae, which live for 7-10 days The life cylcle of a fungus gnat is 3-4 weeks depending on temp and humidity, there are 4 stages, adult, eggs, larve and pupa, the female’s can lay up to 200 eggs, so once you use BTI the problem will get worse before it gets better. It often takes at least 2 weeks to see things level off and up to a month to see improvements in control. I’ve had luck with nematodes too but they need the right soil environment to thrive and they are more expensive in the long run, I generally bring them in if I see thripes and even then i continue using BTI. Gnatrol or mosquito dunks work well. If using mosquito dunks, I like to soak them in a container for a few days to help break them up. My company requires me to use all OMRI or better certified products so we use Gnattrel WDG, but its rather expensive. In the meantime use yellow sticky traps and put them up above head and plants so you don’t get gooped up and also cut them up into about 2 inch squares and attach to plant stakes and stick in soil, the mothers lay the eggs in or on the soil. Good luck
Steinernema feltiae is going to be the most effective nematode for fungus gnats.
We also use a product called SLF100, which has several beneficial microbes, including BTI. It has the benefit of helping deal with nutrient lockout and breaking down the crust on the top of our soil (we grow with organic/carbon based nutes).
Be sure to use the three beneficial nematodes heterorhabditis bateriophora (Hb), steinernema feltiae (Sf) & steinernema carpocapsae (Sc). Sf is probably the most applicable for gnats, but you should be watering in nematodes periodically if you are going for an organic soil grow. Monitor your soil temp to make sure it is inline with the plant’s and beneficials’ needs. You should be measuring and monitoring your beneficials’ levels. Spray with Nuke 'Em, its an organic spray works well. Don’t spray with it if you are using beneficial insects. It won’t hurt the nematodes. Use yellow stickies both as a monitor and kill device (deploy in overabundance). Don’t bring in outdoor soil or clones if possible.
If it is an ongoing problem then spray with OMRI listed products, disinfect and implement an overkill IPM routine. Be sure to use as many methods at the same time as you can. Anything disrupting our grow drives us nuts.
Have you been able to get rid of the problem?
I was wondering if any of our members have used nematodes in a larger grow op (more than 400 plants). Is it feasible? I was thinking of incorporating nematodes into our overall IPM strategy, but can’t find any information on using them at scale.
I like to start my research with our state university extensions. While not always directly applicable to our crop, they tend to offer answers that scale. The video at the bottom seemed pretty solid.
I don’t have a problem…just working out some details on my IPM regiment for our next grow. Thanks for the info.
We have two Bays, each with over 450 plants. We use nematodes in Prop. during Veg. It is something we do regularly. I don’t have specific info on hand. We have applied them in the Bays as well. Just have to pour them in the pots by hand. No pumps or mechanical mixers.
We almost have, the numbers have dropped significantly. Sorry haven’t been on here in a long while.
We are doing it on a multiple thousand plant scale so yes it will work. Just using them on the beginning of the veg cycle.
WOW !! Fungus gnats get around !! Even Alaska !