Rearing Nematodes (aka Eliminating Fungus Gnats Forever)

Advanced Techniques
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I think it’s safe to say steinerema feltiae nematodes are the most effective treatment for fungus gnats. they’re microscopic worms which prey on the larva, killing them then breeding inside their corpse for a couple generations until they burst out to find another host. the only problem is repeated treatments are required (every 7 days), and they can be slightly expensive (at least in canada).

i’m going to document my attempt at rearing my own nematodes so i never have to buy them again! thankfully its extremely easy and cheap!

the required supplies are :

order your s.f. nematodes online or wherever you can buy them and wait until they arrive to purchase your waxworms so they’re nice and alive

once you have both, mix the nematodes as instructed (unchlorinated or distilled water is best). you want to inoculate with 20-30ml @ ~15,000-30,000 nematodes/cup, i mixed 5million nematodes in 5 litres (250k/cup) then diluted 3ml of that solution to 30ml to get ~25k/cup

use a 1oz shotglass or oral syringe and wet the entire surface of the cup of waxworms, using ~30ml for each container, then close it up and mark it with the date (and strain if using multiple) and place them in a cool dark place

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3-4 days after inoculation ~90% of the waxworms should be dead

7 days after inoculation add small amounts of moisture with a spray bottle. continue checking moisture levels until a yellow film begins to develop

12-14 days after inoculation a yellow film should start to develop inside the cups, which is the juvenile nematodes emerging … application can begin 1-3 days after they emerge, can be used up to 5 days afterwards

when ready to use empty the contents of your worm cup on to a mesh screen and gently flush (using non-chlorinated water) all nematodes from the sawdust and cadavers into a dishpan or container until you have accumulated apx. 1 gal of water…

before applying the nematodes to your garden, follow these steps again to start another cup or 2

the nematodes will stay alive in non-chlorinated water for a week or more so you can save half to re-apply 7 days later, or it would be a good idea to have waxworm cups staggered a week apart so each week you harvest a cup of nematodes for your garden and inoculate a new one.

when applying nematodes make sure to agitate your container frequently to prevent them settling on the bottom … they work well in a sprayer and can withstand up to 300psi

@LemonadeJoe it wouldn’t let me create new tags so i didn’t use any

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I’m intrigued. Please keep updating.

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Very cool, indeed! Looking forward to more…

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This is why the internet is so powerful! Bring on the findings.

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Nice idea, I may have to check out my local pet store. I love a good DIY…

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I watched a video they showed the nematodes attacking a host and all that they also showed this fungus warring with the todes and the fungus grew all these crazy traps and attack spores snares it was crazy look forward to updates grow on

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Great thread interested in results!

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Watching closely as I have a few fungus dickhead gnatticus In my room and todes are expensive here too

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This is a very interesting read :slight_smile:

@Esrgood4u have u read this?

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Yeah I’ve been quietly following the thread mate. I’ve not had any problems like this but it’s good to know the information is here incase I ever do.

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yup i got the waxworms from petland, but 25 waxworms was double the price of 100 mealworms so hopefully the mealworms work well … i figure the waxworms are much bigger so it gives the todes more time/space for breeding because i think they go thru 2-3 generations before emerging

my only concern was if my nematodes froze to death, i tried using my 100x scope to see them but it wasn’t working for me… the MSU video recommends a 10x optical microscope or magnifying glass

this is the video i kinda followed, and an accompanying PDF brochure with all the steps

here’s another method of rearing them using petri dishes instead of cups, this is more in depth and involves manually counting the nematodes to calculate population density

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Bugs eating bugs.

Its what it is all about.

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I had thought that nematodes could be seen with the naked eye, was thinking I had spotted them on a microscope slide after finding them in the sample with magnification first I think most are over looked due to there coloration.

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I decent pic for the thread’

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A close up for ya’ll!

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well my experiment has to be placed on hold because the nematodes arrived dead … sending them back to amazon and not sure what to do, i’ve contacted a couple canadian companies and asked if they can guarantee live arrival … unfortunately i can’t find anything available in my city yet :frowning:

the friggin fungus gnats are getting out of control so i think i’ll try playground sand for now

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While off topic have you used bti at all? When I had a infestation to the point it was like a bad fruit fly infestation we’ve all seen at least once (the bachelor sink fly zone where you’re afraid to have an open drink nearby) I had used a combination of mosquito bits on top of the soil as mulch, nematodes, and bits brewed into a concentrated bti tea. 2 weeks before harvest is when I bothered to do the nuke strategy. It actually worked really well and by the end they were gone. Too bad it was harvest when they finally all fucked off and left.

I know better this time what to do and that also my soil is way too high in silt content. Looking to be 4:1 clay:sand with silt at looking around 3x more than both combined. That makes it a 15:4:1 silt:clay:sand ratio​:sweat_smile:. Damn why did I not listen before when I was told to amend the soil?:thinking::man_facepalming:t2:

Ranting, but if it’s that bad it may be time to nuke the pests. IDK if it was because I used bti in both liquid and granular form working on the adults and larvae with the nematodes working on the larvae as well. It could be that I lucked out too and they just left for whatever reason.

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iirc BTi works by coating the plants roots and when the larva eat the roots they eat the BTi and it kills them, and nematodes actually hunt them out and kill them … playground sand should work well by preventing their access to the soil to lay eggs and preventing the juveniles from getting out,

when i looked around before i couldn’t find mosquito dunks anywhere locally and they were kinda pricey on amazon … the bits aren’t available in canada at all that i could find

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Damn that sucks. Still dunks work also. Worst case scenario you know what can nuke them. I’ll be adding some bits to any standing water I have res water included if I feel like pre mixing it a day or so early. Surprisingly it helped out with the fruit flies too. Those bastards never leave me alone as they come from next door every time I get rid of them.

That’s why I keep the spiders that roam in alone. Best pest control is nature’s natural course. Find what preys on them and sick it after them. Conveniently the spiders don’t like it near the lights, so I can let them find the hidden nests and eat all the bugs.

Overall I’m not seeing any pests this grow. The few fungus gnats that come near leave the house now after trying to nest in the soil and not liking it. The garlic is doing it’s job well.

Speaking of try a garlic tea and/or growing some garlic in the soil at least 4" from any nearby plants to be safe. DE is very good too in place of sand, but the sand does it much better. I remember that it can suffocate the plants if done wrong though, but you got this.

Alternative is plant a marigold on the soil and just forget your worries :thinking: I always forget that that plant is so useful when mixed with garlic and chrysanthemum. Though I’m not sure I want even a natural pyrethrin in my soil, so I’ll probably stick to just garlic and marigold as pest control with a application of DE once in awhile.

Clovers might be useful too as they’re living mulch making them a much tastier treat right at the soil. In combination with the rest I’ve mentioned it’s like a ticking time bomb for them.

IDK how far you are into your grow RN, so it may be too late for any of these suggestions, but I thought I’d chime in with what got rid of them and is keeping them away.

If I never shared the link give this a look. None will do it all, but it’s a nice introduction to an IPM. Also the benefits they provide while small are not insignificant. Some don’t even need to be in the same soil to help out. Mint for example you can just plant in solo cups and make a barrier so to speak. I love old world farming techniques that have been successfully used for 1000s of years nearly unchanged.

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Oh Bummer!!! Hope you can find more successfully

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