Gnats !

[BII]

....Spinosad is something I know I can get locally here as I have used it before. I didn't know it worked to help control gnats as well......

Spinosad is effective against adult-form insects, those crawling and flying around,, while Bt attacks the larvae stage.

 

[MesaBoogie]

Spinosad is effective against adult-form insects, those crawling and flying around,, while Bt attacks the larvae stage.

I've hit them so hard with BT for months that I think they are starting to like the stuff. I use wooden skewers to train and tie down my plants. When I pull up the skewers a few days after watering with bt/dunks I can use an eye spy and see the lil larvae bastards squiggling around on the sticks. I'm almost positive they have built up an immunity to it. I've had a few weeks reprieve where I think I've got them and only see maybe 1 or 2 in a week. But then they just come back again even stronger. Will see how those lil f'ers like Nematodes and Spinosad !

EDIT: just a lil side note/rant. I thought for the longest time that there might be another source that the gnats were infesting me from. But now that I have a way of actually seeing the larvae survive in treated soil I'm doubting that.

 

[BII]

I've hit them so hard with BT for months that I think they are starting to like the stuff.......

Maybe you need to try a different Bt product? Maybe your dunks have gotten old, lost efficacy. Also, Bt products differ; can have different amounts and ratios of Bt spores, toxins and bacterial fragments/solids. Maybe try a liquid concentrate made/marketed for use with garden and tended plants (such as from Safer, Monterrey, Bonide and other major brands) vs. messing with, such as grinding, dunks/chips made for dropping into outdoor water sources.

I've used MICROBE-LIFT/Biological Mosquito Control (see Amazon product ASIN B0006JLMQG) for years and never seen any gnats. With it very concentrated, only a drop(s) is needed, the smallest size available can last years.