How to Kill Gnats' Eggs in Your Houseplants
- 1). Tilt the houseplant on its side and twist off the container. Dump the dirt from the container into a trash bag. Secure the bag and throw it away. Pour new potting medium into the container.
- 2). Shake the plant gently to remove some of the old potting medium containing eggs from the root system. Create a hole inside the fresh potting medium that is twice the size of the root ball of the houseplant and at the same depth it was planted. Place the plant inside the potting medium and pack soil around the base.
- 3). Apply a soil drench to the container. Use a soil drench that contains Bacillus thuringiensissubsp. israelensis. The insecticide kills fungus gnat larvae by infecting them with a bacteria that causes them to starve. Re-apply as necessary.
- 4). Spray the houseplant with a pesticide to kill adult fungus gnats. The pesticide should contain an active ingredient such as bifenthrin, cyfluthrin, permethrin or lambdacyhalothrin. Apply the pesticide to the foliage of the houseplants.
- 5). Place yellow sticky cards around the houseplant. Sticky cards draw adult fungus gnats and trap them, reducing infestations and giving gardeners a clue when an new infestation has occurred.
Source...