Fungus gnats can infest potted plants, and the insects can be difficult to control.
The active ingredient in Mosquito Bits® is a biological larvacide called BTI (Bacillus thuringiensis subspecies israelensis). BTI is a naturally occurring bacterium that’s deadly to both mosquito larvae and fungus gnat larvae.
Fungus gnats lay their eggs in the potting soil of houseplants and container plants, and the larvae live in the moist potting mix. In the larval stage, the fungus gnat maggots can cause plant damage by eating plant roots. After about two to three weeks, the fungus gnat maggots pupate to become the tiny black adult gnats that often take flight in a cloud of insects when a potted plant is moved.