How to Get Rid of Gnats on an Orchid Plant
Orchids are rarely afflicted by insect pests except in the case of fungus gnats. These gnats are symptoms of improper orchid care. The small flying insects and their larvae feed upon decaying organic material in the orchid plant's potting material, and also on the plant's roots. If they're not kept in check, the gnat population can explode and become both a nuisance and a health hazard to your plant.
Change your orchid plant's potting material. Only use material that decomposes very slowly, such as coconut fiber and charcoal, and change this regularly every 2 to 3 months. Alternatively, use a material that is inorganic, such as perlite. This removes the decaying material on which the gnats feed.
Reduce watering as much as possible, as the gnats and their larvae prefer a humid and moist environment. Always let the orchid plant's potting material and roots dry out between watering.
Avoid overfertilizing, as this further encourages gnats to congregate on your orchids. Nutrient needs vary widely by orchid species. Consult the nursery or orchid fancier from which you purchased the plant for species-specific fertilization requirements.
Trap and kill the gnats if the preventative strategies do not sufficiently reduce the gnat population on your plants. Use the yellow fly traps used to capture flies and aphids. Setup the traps adjacent to your orchid plant, or hang them from your orchid's leaves. The gnats are drawn to the yellow color where they become stuck and die.
Rid Of Gnats On An Orchid Plant
Inspect your orchid daily for fungus gnats. The wings are clear to light gray and the legs are slender. You may see these pests hovering around the plant. Fungus gnat larvae feed on the fungi that grow in warm, fertile, overly moist soil. Allow the top 1 inch of potting soil to dry out completely between waterings. Do not over-feed the plant. Follow the packaging instructions. Remove dropped or shed plant material and debris from the potting medium surface as soon as you notice it. Glue or staple the end of a wood craft stick to the yellow card. Package the yellow sticky traps up in a plastic bag for disposal in the trash. The gnat larvae will climb out of the soil to feed on the potato within a day or two. Cover the top of the cup with a small piece of clear plastic wrap. The soap in the liquid breaks the surface tension and causes the lightweight gnats to sink rather than walk safely across it.
- Slow-decaying or inorganic potting material
- Yellow sticky fly traps
- "Understanding Orchids: An Uncomplicated Guide to Growing the World's Most Exotic Plants"; William Cullina; 2004
- "The Orchid Grower's Companion: Cultivation, Propagation and Varities"; David Banks; 2004
- South Dakota State University: Fungus Gnats
- University of California Statewide Integrated Pest Management Program: Fungus Gnats, Shore Flies, Moth Flies, and March Flies
- National Gardening Association: Those Pest-y Houseplants
- Iowa State University Extension: Gnats That Drive You Nuts
- Beautiful Orchids: Frequently Asked Questions: How Often Should I Be Fertilizing My Orchids?
- Beautiful Orchids: Orchid Food