Gnats & Beneficial Nematodes

[Lenore]

We've been having a little war with the little bastards of late. Neem oil cuts the population down, but they breed back up in no time.

I've been looking in to natural options.

There's your Bacillus thuringiensis israelensis. The beneficial bacteria found in products like Gnat Off and Gnatrol.
It seems that Bti is no longer available to the general public in Australia. I have found several mentions by different councils that use it for mosquito control, and I was informed that it stopped being stocked on Australian shelves about 2 years ago.
I do not know what import/quarantine laws are involved if one was to buy it for overseas.

 

Then we have Steinernema feltiae, a beneficial nematode.
After a little bit of searching, I was able to find an Australian supplier. And their product called Gnatnem.

Diatomaceous earth is also a handy product. Which we are not currently using ourselves yet.
In a nut shell, it's powdered diatom fossils.
It works by absorbing lipids from the waxy outer layer of bastard's exoskeletons, which causes them to dehydrate.
It is used by putting a layer on top of your medium.
It is also a great source of silica.

I hope this helps anyone waging their own war on the little winged devils.



Lenny.

[georgie]

Hey Lenore,

 

Ive tried the live nematodes before. Cost me about $110 from memory. My Hydro guy ordered them in from Canberra overnight. They came in a white insulated polystryene box. Mixed with water and poured over each pot they worked a treat. I had to leave the oxi -plus out of my nutrient solution for a few days thats all.

 

Have you tried either?

[majicone]

I'm having a similar war!!! Do they harm the plant at all? Or are they just annoying!!! I'v read a few places that those sticky fly strips get them but am yet to try..?.. I'd prefer to keep my baby pesticide free! But if they are harming ill have to take drastic measures!

[The Hash Nibbler]

They are doing more harm than you know mate, spreading disease to your plants and eating the roots under the medium  (the larvae fo the fungas Gnat) . Get some Miterid, mix it up as a drench and smash em now and in 3 days time, then use as a preventative. Mite rid is Neem oil and Botanical oils mixed together, and is non-toxic. Witholding period for it is 2 weeks.

You leave em and think to much, you won't have much to worry about.....

 

Nibbler.

Edited April 10, 2014 by The Hash Nibbler

[majicone]

Cheers for the heads up!!!! Ill irradicate the little bastards ASAP!!

[Lenore]

Hey Lenore,

 

Ive tried the live nematodes before. Cost me about $110 from memory. My Hydro guy ordered them in from Canberra overnight. They came in a white insulated polystryene box. Mixed with water and poured over each pot they worked a treat. I had to leave the oxi -plus out of my nutrient solution for a few days thats all.

 

Have you tried either?

 

Yeah, they're not cheap, but considering what sort of damage the lil bastards can do, it's worth it IMO.

 

We've not tried BB/BN's yet. We've managed to get on top of things.

 

Innoculating your medium with something like Myco Apply Maxx (mycorrhizal fungus, it lives symbiotically in the root zone) makes a world of difference too!

 

Which reminds me, I need to put it on the list again....

 

 

I'm having a similar war!!! Do they harm the plant at all? Or are they just annoying!!! I'v read a few places that those sticky fly strips get them but am yet to try..?.. I'd prefer to keep my baby pesticide free! But if they are harming ill have to take drastic measures!

 

Hell yeah they can harm plants. The larvae feed on the protective coating of the roots which opens the plant up to diseases like pythium (which gnats are well known to carry.) Pythium is one of the causes root rot in older plants and damping off in seedlings and cuttings.

 

I use Eco Neem from Organic Crop Protectants. I've also hit them with OCP's Eco Oil in the past too, and they do not like that at all.....

The Eco Oil is more for things like spider mites and sacrid fly, but I used it as a drench. It certainly helped. Lil bastards evacuated my medium like no body's business!

 

Good luck in your war!

 

Lenny.

[Badseed77]

Innoculating your medium with something like Myco Apply Maxx (mycorrhizal fungus, it lives symbiotically in the root zone) makes a world of difference too!

 This is the best product i have used for preventing gnates . I dont know well it works to eradicate them tho .

  I only grow 1-2 times a year and start about mid/late feb early march . Gnates love the warm weather and i noticed in previous years I had gnates are buzzing around  within the 1st 2 weeks .

I placed a yellow sticky trap down 4-5 days ago ontop of a pot and have not seen a single gnate , not one . I only put the trap down because i had them there and thought why not as i have not seen any bugs .

  Btw majicone those yellow sticky traps dont help much in knocking the numbers down but used more to give you a idea how bad the problem is . Once gnates land on your medium they will be looking the lay eggs .

[Lenore]

Oh yeah Tig, definitely a preventative and not a cure. I noticed the difference in a grow we did and had run out of Myco....

And I love those sticky traps.... Certainly helps keep an eye on numbers.

I need to get some more of those too....

[ehle_fan]

Sticky traps!