Summit Mosquito Bits®, a popular biological control that kills mosquito larvae, is now also approved for the control of fungus gnats. The active ingredient in Mosquito Bits® is a biological larvicide 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 often lay their eggs in the potting soil of houseplants and container plants, and the larvae live in the moist potting mix. 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. To control fungus gnats, shake the granular Mosquito Bits® onto the potting soil in houseplants and other container-grown plants (or mix the Bits into the potting soil prior to planting). When the plants are watered, the BTI in the Mosquito Bits® will be released. After subsequent watering, the BTI is washed below the soil surface. Fungus gnat larvae feed on the BTI and die. The BTI in Mosquito Bits® also kills large mosquito larvae outdoors when spread on standing water where mosquitoes breed.
An 8 ounce package of Mosquito Bits® sells for the suggested retail price of $9.99 at home centers, hardware stores, garden centers and www.naturehills.com.