Pest identification

Sick Plants & Problems
#17

I have seen time and time again, people refer to “letting the soil dry out thoroughly”.

I’m gonna call it like it is. So here’s what:

I don’t know how much water you think a gnat larvae needs in it’s environment to stay alive, and how long a drought needs to be to break a cycle, but I can tell you one thing, if you are going to keep your gnats in check by using water levels, you aren’t gonna grow much.

Soil needs to have moisture to live. Roots need water to live. When you let soil dry out to bonedry (the levels needed to kill gnat larvae would be one where your plants hang drooping for days), only to overwater just to be able to get the now hydrophobic soil back into a water loving state, then you are effectively not just killing a few of them fungus gnats, but you are also killing a vast portion of your precious root system.

Try it out. You don’t even need the fungus gnat infestation for it. Just stop watering, until your plants hang drooping, and then wait with watering for another few days, because those gnat larvae are just gonna be diggin deeper while you are thinking they are done livin, then when you water again they gonna be up n running back in no time only to surprise you with a repeat infestation that you don’t understand is happening. Only it’s not a repeat. It’s still there. All you did was harm the plant more than the bug, and now you gotta put money in saving an even weaker plant. That’s what that will show you, that a drought for days, is really a bitch for your plant to handle. It’s like your girl getting put in the ring with Mike Tyson. But it’s easier to think that a cheap solution is gonna save you, isn’t it?

And that’s the problem. We all wanna save a dime.

I’ve tried DE as well, but honestly, once you water with that shit on top stuff just gets disgusting. And it stops working too once it’s wet. I mean, it’s a nice theory and all that, but in practice, diatomaceous earth never really worked too well for me. I still have a bucket of the stuff, all I use it for now is to repel an ant species that can’t be eradicated from coming indoors. Smallest of them fuckers still make it through though.

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#18

Sure sure. Plants need water. So do bugs, especially fungus gnats. There’s always that balance. But not acknowledging constantly wet soil plays a role in fostering a “pro-fungus-gnat” environment seems to miss that point. Water properly and you’ve got a good start at a wholistic approach. It’s helped me.

I respect your thoughts on DE, and don’t necessarily disagree. Diatomaceous earth isn’t a panacea. But it is another way to create an unfriendly environment for bugs and it’s harmless to humans. Messy? You betcha. It’s part of the trade off and with discipline it can be minimized. I reapply once the soil has dried a bit, and agitate the soil to breakdown clumps once dried.

The dunks/bits always seem to do the trick when it gets that far, but honestly, with proper watering, soil sterilization prior to use, and periodic DE, I don’t have “gnat issues” most of the time these days.

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#19

Ugh! I’m jealous of those mosquito bits! It’s one of the things the average European grower can’t usually get their hands on, sadly! I’ve had the opportunity once but cash was tight, but that’s the thing I hear constantly, that the mosquito bits are the one thing that reliably works every time. And IIRC it’s natural too, which is a very big plus in my book.

And I hear you on the friendly/unfriendly environment. It’s just that my approach does not lend itself well to letting the soil dry out. I’ve started taking the opposite route. Kill all incoming eggs before using the soil, then add water with optimized levels of oxygen by bubbling ozone through the feed water before watering the soil, never letting it dry out more than half an inch of dry topsoil.

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#20

So these gnats are attracted to the colour yellow?

What are the Mosquito bits?

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#21

No, but the sticky trap manufacturers would like you to believe so.

I’m not buying it though.

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#22

There are alternative sources for the active ingredients, take a look in this thread:

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#23

Yes they are:

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#24

Well as far as colored “stickys”, I’ve deployed blue and yellow side by side and the gnats appeared to favor the yellow by far. The thrips didn’t seem to care.

Mosquito bits are safe for humans and animals and use bacteria that , when consumed by them, make it impossible for mosquitoes and as the case may be, fungus gnats, from being able to digest food.

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#25

Correct me if I’m wrong, but making mosquito bits yourself requires having a strain of Bacillus Thuringensis Israelensis, does it not? Because that’s the stuff I can’t seem to find anywhere in Europe.

I’ll consider myself corrected on the colors!

#26

Thank you, I appreciate the info. :grin:

#27

Sorry mate. I’ve no idea about DIY for bacterium based pesticides. But I believe you are correct about the species of bacteria used in mosquito dunks, Wondering why the EU restricts this type of pesticide? Perhaps there’s a detrimental ecological impact outside of gnats and mosquitos?

#28

I find that interesting, :face_with_monocle:

I have a homemade trap I’m going to try. 🪤

I’ll get back to you. :grin:

#29

I doubt it’s so much restricted, more that the manufacturer hasn’t taken the time and money to conform to EU regulations regarding labeling and such, if they don’t want to supply a potential new market, then, as a potential new consumer, you are, as they say, shit outta luck!

#30

I have read that covering your medium with steel wool works. The idea being adults get shredded trying to get to medium and hatching babies get shredded trying to get out. Steel wool will rust as you water through it but that just adds a bit of iron to your medium. Steel wool is made from non toxic metal. Just a thought. I have never tried it but the info is easily available to Google if you wanted to check it out.

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#31

Pantyhose too I’ve heard

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#32

A couple of releases of nematodes always works for me. If you’re growing synthetic then just let the pots dry out fully between watering and they’ll die off, but for organic soil you don’t necessarily want to ever let it fully dry out. Hence the recommendation for using nematodes. Sticky traps won’t really do too much to take enough of em out but allow you to monitor infestation levels by seeing how many you have stuck to the traps

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#33

Thanks for the tip. :+1:t2:

“Curly Kate’s”, is what my mom used to call the steel kitchen scrubbies. I’m pretty sure we can get them at the Dollarama here :canada:, so that’s good to know. :slightly_smiling_face:

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#34

Good thing I have some of those hanging around in a drawer somewhere, that I never, ever intended to go into for formal purposes again. :grin:

Thank you. :slightly_smiling_face:

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#35

Yeah, steel wool is readily available and cheap. As I say I have been lucky to have never had the need to try it, knock wood, but the theory is sound. There is actually a bunch of sites that reccomend it as a solution.

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#36

I haven’t done it but I’ve heard of it working by covering the drain holes. I guess you’d have to tie the top around the stem or something.

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