Safe Pesticides for Plants to Kill Gnats

Sticky Traps

• Sticky insect traps can be purchased online or from home and garden centers. They are effective for indoor gnat infestations in house plants or around food preparation surfaces. Non-toxic and safe for family and pets, the sticky traps capture gnats and other household flying pests. Sticky traps can help with indoor gnat control but are not very effective in large garden areas.

Biological Control

• Commercially available Steinernema feltiae nematodes can be applied to help control fungus gnat larvae in garden or container soil. Nematodes are self-reproducing, although several initial applications might be required to establish a strong nematode population. Nematodes are mixed with water and applied as a spray or soil drench at five- to seven-day intervals. Nematodes are most effective when temperatures are between 60° to 90°F. You can buy nematodes online or from greenhouse and nursery supply stores. Follow the application instructions on the package.

Chemical Control

• Pyrethrins is a commercially available chemical with low toxicity to people and pets. Botanical pyrethrum is made from the flowers of chrysanthemums and is available for purchase online or from greenhouse supply outlets. Apply following package directions. When choosing a safe pesticide for houseplants, select a product containing cyfluthrin, bifenthrin, permethrin and lambdacyhalothrin.

Cultural Control

• Fungus gnats thrive and breed in moist conditions where there is a large amount of fungi and decaying vegetation. Gnat control is similar to mosquito control. Avoid excessive watering, and provide adequate drainage. Allow houseplant soils to dry between watering. Outdoors, remove freestanding water in plant container saucers, yard decorations and children’s toys.