Bad Fungus Gnat Problem - What Else Can I Do?

I've got a huge Fungus Gnat problem, and It's starting to make me mad. Here is what I've tried so far: I tried the Hydrogen Peroxide method of control - Not all that successful. On the House Plant Forum it was suggested that yellow sticky traps and Mosquito Dunks left in your watering can will eventually rid your plants of the nasty buggers. Well it has been 2 weeks and I've seen very little difference in the numbers of Gnats. You can see be this picture (not very appetizing is it) how many Gnats are involved. On the back of the card you can hardly see any yellow left. There has to be at least 300 on there. The plant that is infested the most is my multiflora, and there is a lot of Coir in the potting mix. I don't know if that is contributing to the problem or not. Does anyone here have any other suggestions as to what else I can try? I really want to rid myself of these nasty things. I'm open to any and all suggestions including chemicals.

Doug

Doug, you could try a soil drench with neem (if you want to be organic) or use BATSS (Bayer Advance Tree and Shrub Systemic). For the soil drench, I have used full strength neem before (2tbslspn/gallon), but I think half strength might be safer (1 tblspn/gallon). I have used that strength a lot this year, as a spray, and had just as good results as with full strength.

Doug,
I have used a product called Gnatrol made by BetterGrowHydro. I used it for fungus gnat control with some seedlings and it worked very well for me. It is a BT (bacillus thuringiensis) based biological larvicide. I bought mine in a quart size from Better Grow but you don't need a lot of it. You may be able to find a smaller size elsewhere. It doesn't kill adult gnats but once the larvae are killed the adults die off quickly.

Robin

http://www.bghydro.com/

Thanks for that Information Mark. This multiflora is one of the few plants that I have that has not been treated with BATS, because it had never been outside of the house. If BATS would quickly rid me of these Gnats, I have no problem using it. I also have the Neem, and will probably try that first.

Doug

Robin, I have heard of Gnatrol. The active ingredient is supposed to be the same thing that is in the mosquito dunks that I have been using. I wonder if is possible that the dunks are old and no longer effective. I may try to order a small bottle and try that as well.
Thanks for the response.

Doug

Those gnats are awful. They are all over the kitchen this time of year....even if one speck of the sink hasn't been covered with clorox...but NOT in my greenhouse! (knock on wood).

I once was told to put neem pellets around a plant and they attracted the gnats as they decomposed...so don't try the pellets!!!!

Carol

I have gro light stands all over my house and never noticed the gnats until recently.............mainly the gesneriad family...............

maybe they came in the front door from the screened in porch where all the hoyas are hanging...............hmmmmmmmmmmmm i think I am going to treat everything outside with Bayers again.............i did at the middle of the summer but didn't have hoyas then.............

Inside I have gotten the yellow cards and ordered Neem oil just this weekend from violetshowcase....................

thanks everyone

Doug,
First, let me say that you are a man after my heart given the outstanding growing areas you have created. I was majorly impressed with your photos.

Here is the scoop on fungus gnats. They feed on decay. I usually get them in winter when the soil stays damp. Increasing air circulation around the plant makes a huge difference. Have you seen those 4" personal fans? They are great for plants growing on a shelving grow system. In addition, you can scrape off the top layer of soil and use a fork to rough up and aireate the top level of soil. If it is in a plastic pot, I even "massage" the roots by squeezing the pot. Then, replace soil in the top of the pot with a airy soil mix with lots of perlite. This is a no brainer, but, make sure to remove any dead leaves on the surface of the soil.

I have also used a small amount systemic insecicide that can be found in the house plant section of most garden centers. The granules are small and fine and it is easier to sprinkle a small amount on the top of the soil.

Good luck on your war with those nansty creatures!

Mel

Mel,

I really appreciate the time you put into your response! Incredibly helpful information. It seems like common sense, but stuff that I never would have thought of. I've got some work ahead of me when I get home. Thanks!

Doug

My pleasure, Doug.
I meant to add one more method I use. This helps with gnats, makes leaves shine, and gets rid of any insects that may try to take up residence in your indoor plants. If you don't have a removable shower head, grab one that attaches to the facuet. Put the plant in the shower, spray leaves (front and back) with Dow Scrubbing Bubbles. Leave it on for a few minutes and rinse off. This stuff also removes water spots on leaves and makes the leaves glossy and beautiful.
My son used to get so upset with me when he would pull back the shower curtain and find a tub full of plants. Luckily, now he just shakes his head and knows his Mom is just a little wacked. In winter, I usually take at least one plant with me each morning when I shower for work. After all, why waste all that water down the drain?
Mel

thanks so much meltn.............going to copy and paste your answers!

When I see gnats and have the alcohol nearby...I spray with that too!!!

wouldn't that dry out the leaves under light of African violets and other gesneriads..............thanks...........

I don't know. But I do it in my greenhouse on hoyas.

I had some patches of white "stuff" on one of my hoyas. Thought some looked like bugs and others were just clumps. They were making the leaves sticky when I noticed. I rubbed with a qtip with alcohol and then saw this thread. I just went in and gave it the "scrubbing bubbles" treatment and it sure looks better.