Abstract
The paedogenetic gall midge found in 1984 at a factory for the oyster mushroom in Miyazaki Prefecture was identified as Mycophila speyeri by comparison with six known species of the genus Mycophila in the world. It is a known pest of mushrooms in Europe and Taiwan. To confirm whether or not M. speyeri was naturally distributed in Japan prior to the finding, the unsorted collections of the tribe Micromyini to which Mycophila belongs were examined at Kyushu and Kagoshima Universities. No Mycophila was found in 3, 395 adult specimens collected in 1966-95 from various localities in Japan by sweeping possible habitats. A survey of 40 factories revealed that three indoor mushroom factories in Nagano Prefecture experienced an outbreak of the gall midge in 1983-84 while there was no sign of an attack in outdoor cultivation. The factories had all bought “Nameko” Pholiota nameko spawns from the same source. These results suggest that larvae of M. speyeri reached to the factories in spawn introduced from overseas.
