Top-selling BTI mosquito control and horticultural oil also control pesky fungus gnats. Anyone who has grown houseplants has probably dealt with fungus gnats. Adult fungus gnats are tiny flying pests that can swarm like an annoying black cloud whenever an infested houseplant or outdoor potted plant is moved.
Fungus gnats (Bradysia species) are small, mosquito- like insects that commonly infest the growing medium in which houseplants and outdoor potted plants grow. Often, when outdoor plants are brought indoors for the colder months, fungus gnats harbored in the potting mix are brought indoors, where they can quickly infest the soil of other houseplants.