fungus gnats on Bromeliad
Quick answer
If your Bromeliad has fungus gnats, the most likely cause is: Fungus gnats (Bradysia species) infest bromeliads when the potting medium remains consistently damp, providing an ideal breeding environment for their larval stage in the top 2 inches of soil. The adult flies are merely a nuisance, but the larvae feed on organic matter and can damage fine feeder roots, particularly on young pups and seedlings. Overwatering the soil medium is the primary cause of fungus gnat infestations in bromeliads.
Start here:
- 1. Allow the orchid bark medium to dry completely between waterings — this kills gnat larvae in the soil
- 2. Place yellow sticky traps at soil level to catch adult gnats and monitor population levels
Why Bromeliad gets fungus gnats
Bromeliaceae spp.
Fungus gnats (Bradysia species) infest bromeliads when the potting medium remains consistently damp, providing an ideal breeding environment for their larval stage in the top 2 inches of soil. The adult flies are merely a nuisance, but the larvae feed on organic matter and can damage fine feeder roots, particularly on young pups and seedlings. Overwatering the soil medium is the primary cause of fungus gnat infestations in bromeliads.
How to reverse fungus gnats on Bromeliad
- 1
Allow the orchid bark medium to dry completely between waterings — this kills gnat larvae in the soil
- 2
Place yellow sticky traps at soil level to catch adult gnats and monitor population levels
- 3
Apply a layer of fine horticultural sand (1/4 inch) on top of the bark mix to prevent adult females from laying eggs
- 4
Water the soil only from the bottom (sub irrigation) to keep the surface dry
- 5
If infestation is severe, apply Bacillus thuringiensis (Bt) var. israelensis to the soil to kill larvae
- 6
Improve air circulation with a small fan to disrupt the flies' flight patterns
Keep fungus gnats off this Bromeliad
Allow the soil medium to dry completely between waterings; avoid overwatering; use yellow sticky traps to monitor for adults.