FUNGUS GNATS - Fungus gnats are small, dark, short-lived flies, the larvae of which feed on plant roots and fungi.

Fungus gnats are typically harmless to healthy plants but can inflict extensive damage to seedlings.  Their presence can also indicate more serious problems, particularly over watering; they may be feeding on roots that have sat in drain water too long and are thus rotting, or the gnats may be attracted to fungus growing in saturated topsoil. Consequently, allowing the soil to dry may reduce their numbers.