Yes, frogfan. You already told me this, frogfan. Thank you for your concern.

I sprinkled Sevin on my seedlings just one time, over a month ago, on 11/22/2019.

Like I said on here earlier, I left it on for four days. Boy, does it work! I never see any fungus gnats! Not a one! I'm glad I did it!

Glad to hear that, Mary! I will give it a try! Thanks!

josieskid said:I sprinkled Sevin on my seedlings just one time, over a month ago, on 11/22/2019.

Like I said on here earlier, I left it on for four days. Boy, does it work! I never see any fungus gnats! Not a one! I'm glad I did it!

Are you putting it on the leaves or on the soil surface...?

I've been using the mosquito bits.... 1/4 of a tsp in the bottom of the 8oz cup followed by 1/2 cup of potting soil, another 1/4 tsp of the mosquito bits, more potting soil and then another 1/4 tsp mosquito bits. I mix in the bits and spritz with water as I add to the cup, plant the seeds, and cover the cup with a ziplock bag....

Seems to be working although not 100%, but definitely helps.

Only water from the bottom once the seeds sprout...

If I see anything flying, I reach for the Raid House and Garden bug spray (green can).......


..

Yep, just sprinkle it on like baby powder. Then after 4 days, water lightly to wash it off the leaves and into the top inch of soil. After that, everything as normal. No more fungus gnats!!!

I said I'd post a pic if I had to apply the Sevin again. Well, I did have to apply the Sevin again. It's been almost three months since I did it the first time, and it's been so wonderful not to see those bugs! But, all of a sudden I saw about three of them flying around, and decided I didn't want to wait till they laid hundreds of eggs (if they had not already!).

So, the evening before last, I powdered the babies again. I also gave them another haircut!

I think the reason I got them again is because I had to prepare a new flat of soil for more seeds that were germinating. Maybe these new bugs hatched out of that soil. It's just Miracle Grow.

I can't see why they took so long to hatch. Also, I don't understand why they wouldn't be flying up out of that big bag every time I opened it. But, where else could they be coming from in the middle of the winter?

They probably came from the soil. I did have fungus gnats early this season, and they were in the soil. I found the larva in it. After that, I have been sterilizing all of the bagged soil that I have used this season. I am also using water with Mosquito Dunks in it every time I water. I got rid of them, and they haven't come back.

The life cycle is quite long. At 22 C (about 72 F), the egg takes 3-6 days to mature, then they spend about 2 weeks moving through the larval stage, and then another 3-6 days as a pupa, so it could take almost a month from egg to hatching. It would take longer if the temperature was cooler, and shorter at warmer temperatures, I would think.

Thank you for that info, Valerie! You are so smart! Happy Valentines day, sweetheart!

That is good info about the Sevin. I am just now getting going on my planting, all of which is in 5" square pots on shelving in the basement. I saturated the pots with plain water to get the seeds going (were germinated under refrigeration). Going forward, since I did buy gnatrol, I plan to top dress with a small amount of gnatrol in solution each week and bottom water with regular water. My logic is that they gnats like to do their business generally in the top of the pot, at least to start. And, the organisms in gnatrol will find and feed on the larvae, multiplying as they go. I don't expect a complete weekly die-off of the BTI bugs, based on comments I remember from another thread.
However in the event that none of this works, I do have some old Sevin in the garage

I would do an occasional bottom watering with water containing some of the gnatrol. I have found gnats hanging around the holes in the bottoms of the pots. Once I added some mosquito dunk water to my watering can when I bottom watered, I finally got rid of the last of them.

This afternoon, I moved all my pots off the shelves and checked them all, wiped off the shelves and I am clear of fungus gnats. This is the first time in 3 growing seasons that I have totally gotten rid of them, so persistence pays off.

Valerie, that is wonderful news!

Yes, I am very happy this has worked. Ontario banned most pesticides for household use in 2009, but bti is allowed to be sold and it worked, so that is the good news!

thank you Valerie! I will do that! Last year I used "Mosquito Bits" stirred into each can of water I used, and I also sprinkled them in and around the plants.

It did not work. It had no appreciable effect on the gnats.

And so, I am most hopeful about the gnatrol. Also, I am starting the plants in my basement, which is currently 57 degrees. I hope the gnats hate that temperature.

They will most likely have a much longer life cycle at that temperature, but they will hatch. I had them in the basement and the temperature was in the 50's.

I wonder why the mosquito bits did not work. I believe it is the same formula as the dunks, but one is pressed into a ring and the other is loose. I have been leaving the dunks to soak in the water, and just adding more water, and adding another chunk of the dunks to my water container every few weeks. I strain the dunk water through a net, and add more water to the container to replace what I take out. I read somewhere that it takes 24 hours for the bacteria in the dunks to become active. I don't know if that is true or not.

Please keep me posted on the gnatrol. I would have to order it from the U.S. and it would likely take a couple of weeks to arrive, but I am planning on ordering some next year well in advance of seedling season. This season, I could purchase the dunks locally, so that is what I used because I didn't want to let the fungus gnats breed freely for two weeks while waiting. Anyway, it has been successful, so far, along with sterilizing all bagged soil.

As I mentioned, I did bottom water, as well, because I was finding them crawling around on the trays and under the pots.

Top watering with a Gnatrol solution is all you need. The active ingredient will work its way down with the water. Gnatrol and other strains of BT aren't intended to have any effect on the adult flies, only on the larvae. Also, Gnatrol isn't like beneficial predatory insects which have to seek out their prey, the larvae only have to ingest the BT, and the bacteria go to work on the digestive tract of the larvae. You'll still have the flies flitting around until they disperse or die, but they do no direct damage to the plants, they will lay more eggs though. I use yellow sticky traps in conjunction with the Gnatrol, in order to get as many of the adults as I can.

If I can't get Gnatrol, or I'm not feeling particularly "crispy", I spray Bayer 3-in-1on the plants and soil and call it done.

James, what does "feeling particularly "crispy" mean? Does the Bayer 3-in-1 work?

Problem with bacterial insecticides is that they are not 100% of what they say is on the label. There is a constant variability in bacterial "species" that cannot be controlled even in the laboratory found in these products. What your getting then under the same label will not be the same from batch to batch. Nematodes being more definitive and intelligent are 100% what they are labeled. They are very effective, easily as and more reliable than bacteria. Your bacteria toxins can be mitigated by the endemic bacteria of the insect, which is based from one generation to the next in the insect egg, this is evolutionary adaption. Nematodes are far more destructive because they cause two kinds of primary damage. One is by their initial entry into the insect and then their regurgitation of their endemic bacteria that reduces the internal structures of the insects and the subsequent mating and production of more nematodes feeding within the insect finalizes their fate. More nematodes will be released than you have introduce by many many fold. It is a domino effect.

It would seem, from the posts, that the common denominator is growing in the basement? Is it the humidity? I've always given credit to the vermiculite topper for my three year lack of gnats, but now I'm inclined to believe it's simply because they are in house. When the weather gets nice, and the doors are left open, I do see a few. They like to drown in my wine glass, if I forget to empty it at night. That is all the gnat control I do, so far. But, all the info shared is priceless, if I ever need to address a hoard.

thank you frogfan. I am going to watch very carefully, and if I see an ongoing problem despite using the BTI, then I will definitely buy nematodes. I am keeping the plants in the basement, where the temp is in the 50s at this point.