Fungus gnats, shore flies, and moth flies have many generations each year. Outdoors they are most common during winter and spring in interior areas of California. They occur anytime of year in moist coastal regions and indoors. At least some species of March flies have only one generation a year. Each March fly species tends to be abundant during a certain season, usually spring.
Adults feed very little, consuming only liquids, such as water or flower nectar.
The tiny eggs and oblong pupae occur in damp places where larvae feed. Biological control agents are also available to control fungus gnats. Insecticides are used in commercial plant production, but are not generally recommended for control around the home. Most of these insects' life span is spent as larvae and pupae in organic matter or soil, so most control methods target the immature stages, not the mobile and short-lived adults. Monitoring Visual inspection for adults is usually adequate to determine whether there is a problem.