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Gnat problem!

First off, Hi everyone, i'm a newer poster in this forum.

Siliman said:
Some info on BTi. UC Davis vs fnking gnats

Downside: breaks down rapidly, so needs reapplication from time to time. But does kill the larvae bastids but good. Only kills the larvae. Use yellow sticky traps to capture the flyers.

If you can allow the top of your soil to dry, that helps a lot. (Bottom watering: good.) Sand layer on top prolly work. I put on a dry layer of pine fines and that worked to some extent.

One other trick: diatomaceous earth. I haven't tried this yet as the BTi worked so well, but it can be lightly dusted around inner container edges and around the drain holes in the containers. Anywhere the lil bastards walk around. Downside: Must be kept dry to work. Use a little paint brush to apply in strategic areas.

FNking gnats must die.... :cool:
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Bacillus thuringiensis subspecies israelensis aka "Mosquito Dunks" sold at Home Depot and Lowes, was the product that finally got rid of my fungus gnat problem last year. Took a while since it only affects the larva, but it worked 100%. MY initial application involved flooding all containers with a stronger brew, then following up with every watering for a few weeks.

I had tried the sand idea + Neem oil + pyrethrins + fly paper but it wasn't good enough. I noticed they were also entering through the bottom holes in the pots, good luck plugging those up with sand ;)

There's two types of Bacillus Thuringiensis, the more common one in stores and on Ebay is the wrong type which won't work, it has to say "Israelensis" for you to know you have the right one, which happens to be the one in the Mosquito Dunks product. It's not harmful to plants or mammals, except rabbits supposedly. I know it sounds silly but people claim to use it in their dog's water bowls to keep mosquitoes out of them, go figure.

- Steve
 
Welcome Jet! And thanks for the heads up! Now I know I can go to Lowe's! The closest Home Depot is 30 minutes away, but the Lowe's is right around the corner.
The cinnamon may not kill the larvae, but it SEEMS to have worked on scaring all of the other bastards away!
 
Sup HP. A lot of good ideas on here that I haven’t tried personally, but thought I’d add my two cents. Had this problem once and it is the reason why I only work with sterilized soil these days. A solution of water and dish soap (shoot for something fruity smelling if possible) like dawn will work just as well as sticky paper. These buggers are attracted to the solution and get trapped the moment they touch it.


This didn’t solve my issue, just made it much more manageable/bearable. It works fast too, I saw gnats in the solution within minutes of setting it down. If you can kill the larvae you’ll probably get rid of em completely.


Since the cinnamon seems to work with keeping em off your soil, you can probably use that and this solution to get rid of em.
 
Hot pooper,

Bacillus thuringiensis is the right choice...you can get commercial name like Dipel or Xentary, just drench your plants...if you use Dipel or Xentary, water ph must be in 5.0,wich is ideal, alkaline PH inactivates the Bacillus. ;)
 
Hot Pooper said:
Welcome Jet! And thanks for the heads up! Now I know I can go to Lowe's! The closest Home Depot is 30 minutes away, but the Lowe's is right around the corner.
The cinnamon may not kill the larvae, but it SEEMS to have worked on scaring all of the other bastards away!
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Hey HP, thanks for the welcome. Hope it works for ya as good as it did for me. Remember the first time i used an extra strong brew by letting mosquito dunks sit in warm/hot water for 24 hours, then i thoroughly soaked my containers till the soil was flooded. I followed up with every watering, but used a regular strength brew for maintenance. Also: the warmer the water, the quicker the dunk disolves. The adults don't live very long but some cheap $3 Lowes fly paper can help finish them off.

hector.jacob said:
Hot pooper,

Bacillus thuringiensis is the right choice...you can get commercial name like Dipel or Xentary, just drench your plants...if you use Dipel or Xentary, water ph must be in 5.0,wich is ideal, alkaline PH inactivates the Bacillus. ;)
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Hi HJ, the products you posted may have the wrong strain of Bacillus thuringiensis. From what i understand the Israelensis strain is the right one for gnats and mosquitos whereas the other strains seem to be made for caterpillars, hornworms etc

Wikipedia article on BT-Israelensis: http://en.wikipedia.org/wiki/Bacillus_thuringiensis_israelensis

Dipel PDF's: http://www.planetnatural.com/planetnatural/images/dipel-dust-label.pdf

XenTari PDF's: http://www.valent.com/agriculture/products/xentari/label-msds.cfm

Shoontok said:
Will the same poisons and techniques used for ant eradication also work on gnats?
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Hey Shoontok, it's Sjetski from the Gardenweb forum, good to see you here also!

Personally i'd think twice before using a poison in a way it wasn't designed for, for all we know some of those chemicals may leach into your fruit/vegetables, i wouldn't take that chance unless i had concrete info to back it up.
 
Well, I tried the cinnamon and the peroxide solution the other day. My plants started looking sick last night, and figured I would double check them this morning. Bad news...about 50% of my seedlings are now gone. From what's left, I scraped/washed all of the cinnamon off of the plants (because you can only rinse the peroxide off), added newer soil, and re-watered. It looks like I might lose a few more. I guess we'll see in the next couple of days.
I dont know whether it was the peroxode solution or the cinnamon, but either way, I wont use either one again. I was just being cheap because I am super broke this week and cant get anything from Lowe's until tomorrow. Im not mad either. More upset that I lost some babies. But, #1-I was the one that put both on the plants. And #2-that's why I plant extras. That way if something like this happens, I'll have extras. I also have more seeds, so I should be fine.
 
sorry if i missed it, but are you against using pesticides? ddvp will kill just about every single insect it comes in contact with. dosent harm plants at all far as i know.

http://www.amazon.com/gp/product/B0019BK8AG/ref=pd_lpo_k2_dp_sr_1?pf_rd_p=486539851&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B003A2E394&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1EAMP77C7Y2H22SY92W1

use as directed
 
That sucks man! I doubt it was the cinnamon though. I sprinkled it on every single cell after sowing seeds almost a month ago and will do it again when I pot up this weekend. I read a bunch about it before trying it and never saw anything about it hurting seedlings. Best of luck to you with the survivors.
 
Sorry to hear about the seedling die-off HP, just guessing here but the peroxide solution may have been too strong on already weakened seedlings (fungus gnat larva nibbling on the roots etc etc). But don't scratch peroxide off your list in the future, it has too many uses for a gardener, especially for killing harmful non-beneficials in the soil prior to planting, or a weaker solution for more established seedlings. I highly doubt the cinnamon was responsible.


queequeg152 said:
sorry if i missed it, but are you against using pesticides? ddvp will kill just about every single insect it comes in contact with. dosent harm plants at all far as i know.

http://www.amazon.com/gp/product/B0019BK8AG/ref=pd_lpo_k2_dp_sr_1?pf_rd_p=486539851&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B003A2E394&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1EAMP77C7Y2H22SY92W1

use as directed
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Hi queeQueg, I used the exact same product you linked, and counted 3 dead adult fungus gnats, they don't seem to be attracted to it and almost seemed to stay away from it. After a few weeks i gave up on it and ended up soaking it in hot water and used the concoction as a misting spray. Not sure how well the spray worked on the larva but i never actually soaked my containers with it so i can't comment on that part. I soon started using the dunks exclusively after that.


hector.jacob said:
Jetchucka you are right, Bacillus thuringiensis var. israelensis is a highly selective larvacide. ;)
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I find the narrow selectiveness amazing, sometimes i wonder how people discover/invent these things ;)
 
Jetchuka said:
Hi queeQueg, I used the exact same product you linked, and counted 3 dead adult fungus gnats, they don't seem to be attracted to it and almost seemed to stay away from it. After a few weeks i gave up on it and ended up soaking it in hot water and used the concoction as a misting spray. Not sure how well the spray worked on the larva but i never actually soaked my containers with it so i can't comment on that part.
Click to expand...

DDVP is a super volatile gas, you have to contain it for a few hours at least to get the effect needed. i think it kills with less than 1ppm its amazingly potent and similar to nerve gas. from what i understand most people that use these to get rid of gnats and mites put their plants in a tent bag or some kind of sealed room and let the the gass accumulate.

its an organo phosphate and hyper toxic to insects, i think its ld50 for mice is at ~30ppm so its considerably less toxic to mamals.

anyway i hope you wore gloves when you were messing with the resin to make that spray.
 
queequeg152 said:
DDVP is a super volatile gas, you have to contain it for a few hours at least to get the effect needed. i think it kills with less than 1ppm its amazingly potent and similar to nerve gas. from what i understand most people that use these to get rid of gnats and mites put their plants in a tent bag or some kind of sealed room and let the the gass accumulate.

its an organo phosphate and hyper toxic to insects, i think its ld50 for mice is at ~30ppm so its considerably less toxic to mamals.

anyway i hope you wore gloves when you were messing with the resin to make that spray.
Click to expand...
Oh great, but you know what, i may have used another brand/product in the exact same plastic holder, i sorta remember "Pyrethrins" being one of the main ingredients. In other words i may not have experience with the product you linked (i hope i didn't poison my liver and kidneys!!). Either way i always proceed carefully, never touch this stuff with my bare skin because some things give me red splotches, and i try to never breath while i'm spraying or avoid spraying into the wrong side of a breeze etc.

Edit: i'm now searching the Lowes and Home Depot website to see what product i had purchased. And crap, i think it's the one you linked. I guess i'll wait for that third arm to grow out of my back :eek:
 
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