Bug FAQMushroom fly
Megaselia halterata · Order: Diptera · Family: Phoridae
Also called: Mushroom Phorid Fly
Source: Wikipedia
Adult mushroom flies are tiny, about 2 to 3 mm long and dark brown in color. They are a common pest in mushroom farms worldwide and can sharply cut mushroom production. The larvae are drawn to fungal mycelium and damage both the mycelium and the gill tissue of mushrooms.
Source: Wikipedia
How to recognize it
They belong to the hump-backed flies and have a noticeably arched back.
Source: Wikipedia
Size
Adults measure roughly 2 to 3 mm and appear blackish-brown.
Source: Wikipedia
Is it a pest in the house?
It is a common pest of mushroom farms and can greatly limit mushroom yields.
Source: Wikipedia
How to get rid of it
Entomopathogenic nematodes are not effective at controlling this fly.
Source: Wikipedia
Where it lives
This species is a frequent pest in mushroom cultivation and occurs worldwide.
Source: Wikipedia
What it eats
Adults are attracted by the scent of developing fungal mycelium. The larvae feed on mushroom mycelium and damage the gill tissues.
Source: Wikipedia
Where it comes from
It can be found across the globe.
Source: Wikipedia
Where it is found in the US
Recorded in 2 of 51 states and DC. Most records: California, South Dakota.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Months it is reported in the US
Source: GBIF
Questions people ask
How can I control mushroom fly infestations?
Entomopathogenic nematodes have been found to be ineffective against them.
Source: Wikipedia
What damage do mushroom flies cause?
Their larvae feed on mushroom mycelium and damage the gill tissue, reducing crop yield.
Source: Wikipedia
Where are mushroom flies found?
They occur worldwide and are especially common in mushroom cultivation facilities.
Source: Wikipedia
Same family (Phoridae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Megaselia_halterata
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-27 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-27.