Cultures of Drosophila (Diptera: Drosophilidae) and Drosophila parasitoids (Hymenoptera: Cynipoidea, Eucoilidae) in the Department of Biology, Imperial College at Silwood Park, England were infested by Proctolaelaps (Proctolaelaps) sp. near scolyti Evans. Mites were brought under control in 6–8 weeks by three measures: (1) fly culture bottles were sealed with non-absorbent cotton wool bungs, (2) infested bottles were immediately destroyed, and (3) emerging flies and parasitoids were screened for mites before they were used for further culturing. Experiments showed that mites could not survive and reproduce on a diet of water or Kalmus medium, but could on Kalmus medium with Drosophila larvae, on live yeast, on Kalmus medium with yeast, or on Kalmus medium with yeast and Drosophila larvae. Predation on Drosophila eggs, larvae and nymphs by Proctolaelaps was not observed, nor was a decline in the productivity of fly culture after heavy infestation with Proctolaelaps. This mite is likely to be fungivorous and might be a competitor/predator of acarid contaminants in fly cultures.