How to Make Your Own Sticky Traps for Soil Gnats

Soil gnats, or fungus gnats, feed on soil fungus and the decaying organic matter in potted plants. These pests don't typically damage plants, but they are an annoyance in the home. The adults lay their eggs in the soil surrounding plants. When the eggs hatch, the larvae feed on the organic matter in the soil. Trapping the flies once they mature prevents them from laying eggs, breaking the cycle and eventually reducing or eliminating the gnat problem. Commercial traps are available, but you can make your own and save money.

Yellow cardboard
Petroleum jelly
Spoon

Instructions

- 1
  Cut a 4-by-4-inch square of bright yellow cardboard. If yellow cardboard isn't available, glue bright yellow construction paper to a piece of sturdy cardboard.
- 2
  Smear a thick layer of petroleum jelly onto the cardboard sheet, using a small spoon. Cover all portions of one side of the cardboard with the jelly.
- 3
  Set two to four cardboard traps around the affected houseplants. Place one or two of the traps directly on top of the soil in the pot if there is room.
- 4
  Check the trap daily and discard it when it becomes coated in gnats. Replace each discarded trap with a new trap.
- 5
  Keep the traps around the plant and continue to rotate new ones in until no more dead gnats are found stuck to the petroleum jelly. This may take several weeks, depending on the severity of the infestation.

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