I was thinking the same thing, I use GO Gnats its cedar oil and kills the Fuckers Dead and is safe to use.Pretty hard core for fungus gnats,try gnatrol. JK
A non-toxic, poison-free alternative! Earth Juice goGnats is specially formulated for use against fungus gnats, midges, spider mites, thrips, aphids and many other garden pests. Can be applied as an area spray or added to fertilizers and used as a soil drench. For hydroponic gardens, it is recommended to add directly to reservoirs on a regular basis as part of a plant maintenance program.
DIRECTIONS FOR USE:
Hydroponic Systems: Mix 1 to 1.5 oz. per 10 gallons of solution. Add to reservoir every 2 weeks at nutrient solution change.
Area Spray: Use 2.6 oz. per gallon of water. Spray directly on infested areas or apply as a barrier. Reapply every 2-weeks.
Garden Plants: Mix 1.7 oz. per gallon of water and spray over entire plant. Reapply every 2-weeks.
CAUTION: Do NOT spray plants when temperatures exceed 90° Fahrenheit, or in direct sunlight.