problem with black fly

Beverly Erlebacher bae at
Wed Jan 29 15:06:40 EST 2003

In article <K9uZ9.5987$RZ.54969 at>,
dave <devilgas at> wrote:
>hi everyone. i've a plant in work that has a considerable number of black
>fly (assuming that's what they're called) that live in/on the soil. does
>anybody have any idea how i can get rid of them?
>the plant is similar to a swiss cheese plant and lives in a 4ft x 1ft x 1ft
>trough. the flies are becoming a problem.
>the flies themselves are virtually identical to green fly only coloured
>black. i've tried spraying the plant and soil with soapy water but this has
>made no difference.
>any help or advice greatly appreciated.

You've probably got fungus gnats, which live on decaying organic matter
in the soil.  You can control them by keeping the soil, especially the
surface soil, drier, or covering the soil with a cm or two of plain sand.
The flies are reluctant to lay eggs in dry or poor soils.

There are also some biological and chemical products that are listed for
fungus gnats, but to save money and avoid pesticides, try the dry surface
route first.

If you need to get the number of adults down fast, e.g. your co-workers
are complaining, fungus gnats are attracted to the yellow sticky traps
sold to control white flies even more than white flies are.

More information about the Plantbio mailing list