The chalk brood fungus, Ascosphaera apis (Massen ex Claussen) Olive and Spiltoir, is believed to have been discovered by Dr H. Priess in 1911 in an infected comb sent to him from the province of Hanover. Beekeepers in the district called the trouble 'chalk brood, and this name has been generally adopted, although 'Ascosphaerosis' and 'Pericystismycosis' are also found in the literature. To have had a popular name by 1911, the disease must have occurred beforehand, and Samsinakova quotes a report from Czechoslovakia in 1878. It is likely that many of the reports of chalk brood in Europe in the early 1900s reflect its coming to the notice of beekeepers changing from fixed- to movable-comb techniques rather than indicating the origin of a new disease. In 1982 Nixon published in Bee World a map showing countries in which chalk brood had (or had not) been reported.