The family Phoridae (Diptera) comprises more than 200 genera, of which the most numerous is the genus Megaselia rondani, comprising about 45% of all phorid species. Larvae of these flies develop in miscellaneous environments, including decaying organic material and plant tissues; many phorid fly species are parasitoids or parasites of invertebrates and vertebrates, including human. The species in the Phoridae have highly diverse life history traits and geographical distributions that are considered to be unmatched in the entire insect order encompassing all flies.

A large group of phorid flies feed on fungus sporophores, but few species feed on cultivated mushrooms. Throughout the world, Megaselia halterata (Wood) is a significant pest in mushroom production. The “mushroom phorid,” Megaselia halterata, belongs to the Phoridae, a very large family (group) of flies comprising more than 3,500 species.

Megaselia halterata is found worldwide, and populations of this fly are especially prominent wherever edible mushrooms are cultivated. This species is an obligate fungal feeder; that is, it cannot feed or survive on anything other than fungal mycelium.

The phorid flies are light to dark brown in color and 1,9-2,0 mm long in size. The wings are rounded apically with anterior strong veins and posterior weak vein. Antennae are 1-segmented with long aristae and the hind legs are slightly curved. The larvae are dirty white with narrow transparent anterior end and visible black mouth hooks. The pupae are dorsiventrally flattened and light to dark brown in colour. The larvae emerging from eggs feed on mushroom mycelia and tissues. In fruit bodies they form tunnels and move upwards. Attack at the pinning stage restrict further development of pinheads and buttons. The flies attack mostly during october-november.

Damage by phorid fly directly occurs, due to the feeding of their larvae on mycelia and fruiting body or indirectly due to the excreta secreted by the larvae which alter the chemical and physical properties of the compost. A research of Evaluation of Microbial Products for the Control of the Mushroom Phorid Fly was held. It was found out, that: “Bti (a bacterial larvicide, Bacillus thuringiensis var. israelensis Berliner) was effective against the mushroom phorid fly, M. halterata , spinosad (biologically-derived insecticide) and Steinernema feltiae, may become viable alternatives to chemicals because they appear as effective as chlorpyrifos-ethyl in reducing fly emergence and larval damage to the mushroom crop. The use of these products in conjunction with good management (in the form of compost pasteurization, fly screening, fumigation of rooms, and general good hygiene) can reduce the use of chemical insecticides, or enable insecticide-free production, and may provide a marketing benefit.”