Gnat/Gnat Larvae Infestation

[hostilis]

Hello everyone. I started seeing these little white long slender bugs crawling around my plants in my grow room and a surplus of gnats flying around. They don't seem to be doing any damage to my plants, but they make me uneasy. Has anyone ever had problems with gnats and gnat larvae? What did you do about it? Did it hurt your plants?

Thanks!

[AndyAmine.]

Bacillus Thurigensis Israeli is the stuff you want.

You can also buy the protein crystals that the bacteria excrete if you prefer but they don’t last as long in the soil/medium.

Edited December 1, 2013 by AndyAmine.

[tripsis]

Get on top of it ASAP. If they get to your cactus seedlings, you will soon see the damage.

As Andy says, you want a product with Bti, e.g. Gnatoff or Gnatrol. You can also get predatory nematodes, but they require refrigeration during transport and until being used. I've not used them personally, so can't advocate from experience. With Bti, you need to reapply a few times to break the cycle and kill any larvae from eggs already present, as it only works on the larvae.

[hostilis]

Thanks for the responses.

If they were gnat larvae would they be crawling around on the tops of the plants or just the soil?

[tripsis]

Just the soil.

They look like this:

[AndyAmine.]

I was all good with my reply until I reread your comment and noticed that you said that you have "little white long slender bugs crawling around my plants.

Fungus Gnats adults are black like small mosquitoes and the larva which are more transperant than white are down in the soil not on the plants, so unless you have 2 infestations going on then I'm not 100% sure what your pest is.

The main reason I bring this up is because BTi is only effective against Sciarid Fly (Scarid Fly/Fungus Gnat) and a few related species like mozzies but its not general purpose.


(EDIT: Hmm, I guess I should have refreshed before I posted, lol)

Edited December 1, 2013 by AndyAmine.

[hostilis]

There are gnats flying around, but then there are little white slender bugs crawling around on some of the plants as well. Also on my pereskiopsis leaves. They seem to be focused on the pereskiopsis. They have lets and they crawl. I almost thought they were the larvae form of the gnats that are in that room, but I guess not. Not sure what they are, I'll have to spray my plants with something I guess. I thought it was under control with the jumping spiders. They seem to keep most of the other bugs in check. But i'm noticing more and more.

(I have a little ecosystem going on in my grow room)

Edited December 1, 2013 by hostilis

[tripsis]

Possibly immature thrips. Some photos would help.

[hostilis]

Shit. It is thripes.... What can I do? They're all over a bunch of my plants! They haven't been doing a ton of damage, not yet anyways, but i want then gone.

How can I kill these fuckers!?

[tripsis]

Yep, thrips. Spray with natural water-based pyrethrum. Make sure it's water based! If you use the common commercial petroleum-based version you will kill your plants.

[hostilis]

okay. I'll look into that. Thanks. Is thrips going to threaten the life of my plants? Or is it more just cosmetic damage?

[tripsis]

Not sure, never had to deal with them personally. They're a major agricultural pest in some areas.

[M S Smith]

I'm with tripsis, use a water-based pyrethrum. I've used it on mites, thrips, and gnat larvae with great success, even on the smallest seedlings. Give the soil around the plants a good soaking. I've never had it cause me any problems.

~Michael~

[hostilis]

Well thanks for the advice. Is pyrethrin the same as pyrethrum? I am searching for water based pyrethrum and I keep finding "water based pyrethrin"

EDIT: after some research I found that pyrethrin is basically pyrethrum. I am just trying to find some water based stuff now.

Edited December 1, 2013 by hostilis

[hostilis]

So here's my attack plan. I am going to get some water based pyrethrum. I will spray all of my plants with them in that grow room. I am also going to set out a bunch of sticky traps to catch the adults that are flying around. I'll spray them every 5-10 days for the next month or so and just keep a close eye. Also I've been killing the visible ones manually. Lol.

They are making weird spots on my loph grafts and it's "bugging" me out. Lol.

[slice]

Bacillus Thurigensis Israeli is the stuff you want.

You can also buy the protein crystals that the bacteria excrete if you prefer but they don’t last as long in the soil/medium.

right on. one time use and thats it. there is a product that i use called gnat off (Bacillus Thurigensis).

Edited December 1, 2013 by slice

[hostilis]

The product I found is called Riptide Waterbased Pyrethrin ULV Concentrate. It has these ingredients: Pyrethrins...............................5.0% Piperonyl Butoxcide.....................25.0%. Is it normal for the pyrethrum to have piperonyl butoxcide in it?

Sorry or all the questions. I'm just want to be sure about this before i buy it.

Thanks.

[tripsis]

Yes, normal. The piperonyl butoxcide makes the pyrethrins more effective.

[tripsis]

Though 25% seems high...

[Sallubrious]

I had a problem with gnats one time.

I wiped them out with diatomaceous earth and a dustbuster handheld vac.

After I gave them a good dusting the first time, I watered the DE into the potting mix and then did it again but this time I let the soil mix completely dry out for about 7 or 8 weeks.

The dustbuster was the easiest way to catch the airborne gnats before the DE & dessication wiped out the larvae.

They never came back.

[hostilis]

The stuff I'm getting is a concentrate that you mix with water and then use.

[tripsis]

Good point.

[AndyAmine.]

You still need to address why they are in your growing space.
They will generaly only coime in if you have decompoising organic material which generaly means either root rot or leafs/debris rotting on the soil or on ther floor. clean up your area and if indoors sterilise with H202 or something.

You may also want to follow up with some kind of root recovery tonic and/or sterilising solution or friendly bac/fungi because they can bring pathogens with them.

Nothing takes on Gnats like BTi (Only use Israeli though, not another strain)
Gnatrol, Gnatoff, Nilnat/Tanlin etc..

To catch the adults make an ACV trap, add some apple cider vinger to a bowl and put gladwrap ontop, then poke a dozen holes in it so they can get in but cant get out. They cant help themself because they luuurv the smell and wind up trapped inside.

If using sticky traps put them a cm above the soil so they jump/fly up and onto it.

If you want to use a physical barrier use CSS about an inch thick at the base and at the top of your pots so they cant get in or out.

DE is good but IME it doesnt work when wet and looses effectivness after a short while so it is pretty useless on things like pereskiopsis which likes wet feet to grow well.

Edited December 1, 2013 by AndyAmine.

[hostilis]

My pereskiopsis soil has trichoderma. Wouldn't that kill off any other culture I put in there?

Edited December 1, 2013 by hostilis

[AndyAmine.]

By that comment Im assuming you are using coco coir?

Gnats love coir and IME the only way you can really get ontop of it is with BTi.

Yes you can mix beni's, generaly speaking they wont attack each other or overly compete.
There is a product on the market that has over 55 different types in the one mix.

Generaly speaking you have 2 ways to go, either sterile or with benifical bacteria and fungi.

If you use a sterilising product like H202 then yes you will kill off your beni colonies but if things are out of control sometimes its better to clear the decks using a sterilising product then restart with your beni's.

Most shops sell beni's at stupidly expensive prices but if you choose the right products and buy online its not so bad and even more so if you use them to brew up your own tea which boosts numbers dramaticly.

Best bet for outdoor use is brewing up your own super-duper worm tea with worm castings + unsulphured mollases and to really make it special add a few pinches of a good beni product that has a wide range of species.

Mix your castings and mollases together and then into a stocking, get a big bucket and tie it onto the rim so that it floats 1/2 way, add water and throw in an air stone or two letting it bubble for 24hrs.
Make sure you use it within 2hrs of disconnecting the bubblers. (you may get longer if refridgerated)

Something to consider is that beni's will only thrive if the temps and oxygen levels are suitable for them, if your pots/soil temps are getting above 30c or are getting water logged then you are killing your beni's through heat and lack of oxygen...

Ive seen some products recently that have nitrogen fixing properties, I imagine they would be great for Acacia species like Phleb.,

Edited December 2, 2013 by AndyAmine.