A woman wrote to us with the picture below, wondering if we can help her identify it. She says that she and her friend have found several of them. We’re not sure where she found it, so we’re going to have to do our best to identify it from the picture below.
“Fungus gnat” is the common name for many, many (over 2,000) species of fly that are classified under the Sciaridae, Diadocidiidae, Ditomyiidae, Keroplatidae, Bolitophilidae, and Mycetophilidae families.. They tend to live in moist environments. In domestic households, they are often found in or near houseplants. If the soil is wet, then fungus, algae, and decaying plant material can accumulate, and then the larvae will gather around to eat it. This particular larva appears to be a bit dried out and is likely not feeling too great. It is likely that it’s dead.
Fungus gnats are not typically dangerous to humans or pets, though they and their larva are not precisely the type of guests you would invite to a fancy dinner party. Partially because their appearance is not exactly appetizing, and partially because they’re notoriously poor conversationalists.
Additionally (and perhaps more important than their poor conversation skills), the larva are a threat to the small roots of rooting plants. If our reader is finding a lot of these in her home, then we recommend that she check the drainage on any houseplants she has. If the plants are overwatered and the soil is continually moist, then the little guys will be quite happy to live there. This is because wet soil is a great source of fungus and decaying plants that the larvae need to eat.
Natural suggestions to control/prevent these household visitors include putting sand on the top of your plants. The sand will dry quickly, and the dry sand will not be an attractive place for fungus gnats to lay their eggs. Traps that consist of small containers of vinegar can help attract the adult flies so they can’t lay eggs, and slices of potato can be used to attract the larva. But we think that the best strategy is to eliminate the wet soil that houses the larvae’s food, and then our reader will find that they leave on their own.
Unless, of course, she does decide to invite a couple to her next dinner party….