Hey crew! Like many growers, I get fungus gnats in my grow from time to time. I often bring bags of compost or worm castings into my grow, which means I regularly risk bringing gnats or other pests in from the outside. I also often have bags or totes of soil or compost in storage around my grow, which creates a lot of potential sites for pests to hide out.
In the past, I’ve relied mostly on sticky traps, nematodes and BTi to control the issue. For the most part it has worked to keep the gnats in check, but lately I’ve been using compost and castings a lot more often, and my old practices haven’t been enough to keep up with the constant threat of gnat invasion.
So…
How do you defend against invasion?
WITH AN ARMY!
DEPLOY THE TROOPS!
😎
Rove Beetles (Dalotia coriaria)
I absolutely love these little guys! They are like little soil commandos! Open the bottle of these guys and off they go! Zipping around the soil looking for gnat larvae or other tasty prey to brutally devour! RAWR!
Within a week or so of deploying these guys my fungus gnat populations dropped off big time. I’ve only used them for fungus gnats, but I’ve read they are also effective for preventing root aphids and other soil pests.
They are commonly sold in bottles of 100, but in my experience, these bottles probably have several hundred little beetles in them. No idea where they got the number 100 from… there has been a lot more than 100 in every bottle I’ve received.
I released a tube of “100” of these guys about 3 months ago and they are still alive and thriving. They lay eggs that hatch little larval versions of themselves and they are happily reproducing and spreading throughout my soil. If anything, the population seems to have increased over the last few months.
I recently added a bunch of new soil into my grow so I did a second release of two vials of “100”. They are now quite abundant and easy to find in all my pots. I’m hoping to keep the population going permanently.
My first order of “100” was from Natural Enemies Biocontrols and it cost me $23. Natural Enemies has a $100 minimum order, so this was part of a larger order. Shipping was $25 for my whole order. Shipping was overnight but it took about a week for my order to ship.
My second order was for two vials of “100” and was from Green Methods. They have a deal where you can get two vials of “100” for $25. They have no minimum order. Shipping was $21. I placed my order on Friday and it showed up on Tuesday, so Green Methods gets bonus points for speed!
Both orders went smoothly and I can fully recommend both companies. For a smaller grow, Green Methods is probably a better option since they have no minimum order requirement.
Stratiolaelaps scimitus (AKA- Hypoaspis miles)
I’ve also been deploying these little soil mites to defeat my gnat enemies.
They are a lot smaller than rove beetles, and look a bit like brown or tan colored spider mites. Do not be alarmed though, these little guys live in the soil and don’t feed on plants. They do feed on lots of bad guys though, including thrips, fungus gnats and root aphid larvae.
These little critters crawl around the soil and explore the mulch layer looking for prey. They have a quick life cycle (13 days!) and will reproduce rapidly. They’ve established themselves quite well in all my pots and have spread rapidly.
3 months after the first release, they are still thriving. Peel away the mulch layer and you can see them happily patrolling the soil:
Its nice to know my soil is not just full of micro-life, its full of macro-life too!
My first order was again from Natural Enemies Biocontrols and cost $28 for a 1 liter tube of 25,000. Natural Enemies has a $100 minimum order, so this was part of a larger order. Shipping was $25 for my whole order. Shipping was overnight but it took about a week for my order to ship.
I also ordered some from Green Methods. I ordered 25,000 for $30.95, but they also have smaller and larger sizes available. Shipping was $21 for my whole order. I placed my order on Friday and it showed up on Tuesday, so once again, Green Methods gets bonus points for speed!
Conclusions
- Soil predators are awesome!
- They are an effective way to prevent or combat soil dwelling pests.
- They will establish themselves in a living soil system, and will stick around even after the pests are gone.
- This makes them especially cost effective for growers that plan on re-using their soil for several cycles. (no-till)
- Ordering live insects requires expensive overnight shipping. Consider teaming up with friends to place a group order to save on shipping costs.
- Natural Enemies Biocontrols and Green Methods are both “Soup Approved” predator dealers.
Thanks for reading!
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Thanks for the info!
Thanks Soup!
Nice man 🤘🏻
Hey soup can u email me at medina.kelvin@yahoo.com. I want to learn more about no till n I need someone I can talk to n learn from.
Nice one soup! Thanks for the idea. Pests detrimental the growth of the plants. We are planning to grow an organic garden and this would be very helpful in order to eliminate the pests. We have been in constant touch with the http://pinnaclepest.com/ pests professionals to get the ways and they suggested that ladybugs, termites and even fly parasites are natural predators, helping us to prevent the very growth of the pests. Thus, now organic gardening pest control is very much possible through natural ways instead of resorting to using chemicals that undo the benefits of organic gardening.
Seems like you preferred the rove beetles. If you had to choose between the the mites or rove beetles which would you pick? I found this site and they have some cheap sachets, but are not fungus gnat predators.
https://www.naturesgoodguys.com/collections/all
They have those as well like you mentioned from the soup approved insectaries.
Those cheap sachets look interesting. I’ve never seen single sachets on sale before, usually you have to order a ton of them. that could be really cool, assuming they are effective.
I’ve seen that company selling bugs on amazon before but I don’t think I’ve ever ordered from them… might have to check them out.
Hard to choose between rove beetles or hypos… they make such a great combination when you use both of them. if It sounds like I prefer rove beetles it’s only cuz I think they’re kinda cute. Lol. Both are great tho.
rove beetles are a lot more mobile and can fly short distances, so they might be more effective if you have a lot of small pots or a large area to cover. I’ve noticed they like patrolling my clone dome and inspecting all my rapid rooters for pests lol. They’re very active and like to explore.
The hypoaspis mites are less able to spread from pot to pot, but they are great at establishing themselves for the long term. Give them a good environment and they will stay forever, especially if you plan on reusing your soil.
Also, keep in mind you usually have to pay for over night shipping to get anything… so if your in for a penny, why not go in for the full pound?
If you are already investing in mites + shipping, might as well get the rove beetles too! When I ordered it was only like 15 or 20$ to add some rove beetles to my order.
So what would be good for the dreaded spider mites? Ive been reading that Green Lacewing larva will do the trick.
Spider mites are best controlled through preventive sprays with oil and soap products. If you get them in veg they aren’t particularly difficult to kill, but you need to be persistent and continue treatment every few days for a couple weeks to totally rid yourself of the problem.
If you get them in flower, your treatment options are a lot more limited, so its best to practice weekly preventive spraying in veg since that will actually prevent most spider mite issues in flower too. If you get a bad mite problem in flower, its usually due to a lack of prevention or scouting in veg. So keep up with the IPM and you’ll usually avoid them all together. (www.dudegrows.com/ipmbasics)
Generalist canopy predators like Lacewings or canopy dwelling predator mites can work well as a preventive or for treatment in the early stages of a mite infestation, but they are usually too little too late when it comes to fighting a larger infestation. Once you’ve got an established mite problem, knocking them back with sprays and then following up with predators afterwards is usually a better approach.
Thanks for the info. I’m trying out a new compost and it apparently came with bugs. I’ve been trying to figure out what they are and I’m now very confident they’re rove beetles.
I’m growing in a tent and they’re flying up. I’ve read they’re attracted to light. They seem to be getting stuck in the trichs on my buds. Have you had any issue with that?