The only real solution to effectively combat fungus gnats. After I've been trying for months, (let it dry yellow stickers, biological insect spray, soil) with all sorts of means to get rid of the critters at great expense, I came across this little worm. After I've applied in accordance with the instructions, the pest backlog fell abruptly. After about two weeks only occasional mosquitoes could be seen, which would presumably over time also died. To speed up the process, I bought a second time, the means and applied again. After that not a single mosquito was more to see - we have been just over two weeks last Schädlingsfrei!
The attack our plants, however, was extremely - under normal to heavy infestation helps a "ration" certainly more than enough.