Mites in fungal cultures.

Recently all existing Trichophyton mentagrophytes colonies within our laboratory, which had originally appeared normal, rapidly and at an early stage became perforated. Therefore the aims of this study were to expose the cause of these major morphological changes and to find out if this phenomenon may occur in other fungal cultures. Microscopic examination of specimens taken from the damaged colonies showed many mites at different developmental stages, which were subsequently identified as the acarus, Tyrophagus putrescentiae. The laboratory experiments demonstrated that mites feed on the spores and hyphae of all the dermatophytes, moulds and yeasts tested. For the time being Tyrophagus putrescentiae is an unpleasant pest which damages fungal cultures but future use of the acari in biological control may be considered.