Fungus gnats and control
Thu, 11 Dec 2003 06:29:06 PST

Fungus gnats are a problem sometimes.  One thing I do is to avoid using peat 
moss unless the seeds really want it (e.g., azalea seeds).  Peat moss and 
too-damp soil can lead to amazing numbers of fungus gnats.  

I have found that insect bombs and foggers (that are marketed to clear up 
fleas inside a home) take care of fungus gnat infestations, and I have not 
observed any damage to seedlings (I suppose damage could happen).  

A sure approach involves misting plants and soil surfaces to wetness with 
pyrethrin or other low-toxicity (for humans) insecticide; this will kill the 
larvae/eggs in the soil.  You just need to be sure that the insecticide is safe 
for your seedlings.  If you don't treat the entire collection of seed pots and 
nearby houseplants the fungus gnats can recolonize quickly.  

One email friend recommended using fly strips (sticky paper), I have not 
tried this approach.  The goal is to trap all emerging adults before they can lay 
eggs in the soil.  

LINK:  OSU Fungus Gnat Factsheet 


More information about the pbs mailing list