The “black flies” that can often be seen on flower windows and winter gardens are usually fungus gnats. They most often occur if the plants are watered too frequently and become waterlogged. The 3–4 mm long larvae of fungus gnats feed on the roots of the plants and can damage the sensitive roots. Plant flycatchers trap the pesky adult fungus gnats so that they can no longer cause any harm. In the event of a more serious infestation, tackle the larvae in the soil directly.
