14 Department Circular 287, U. S. Dept. of Agriculture. 



parasite of certain solitary insects, but does not record any cases of 

 the finding of the mite in such insects. 



Other articles on this disease have recently appeared in various 

 French bee journals, but many of them have statements regarding 

 the disease that are not based on examinations for mites and there- 

 fore are of little if any value in the present discussion. Since several 

 American beekeepers claim to have used flowers of sulphur success- 

 fully in combating the disease of adult bees commonly known in the 

 United States as paralysis, certain French beekeepers are advising 

 the use of this material in combating the Isle of Wight disease, ap- 

 parently on the mistaken idea that paralysis and the Isle of Wight 

 disease are identical. Statements to this effect serve only to confuse 

 the situation and are wholly valueless without experiments to sup- 

 port them. Eennie has repeatedly warned British beekeepers against 

 the drawing of false conclusions of this type. In a recent paper 

 Morgenthaler (66) has specifically warned beekeepers not to place 

 confidence in the use of flowers oi sulphur in the treatment of the 

 Isle of Wight disease and has shown wherein they may make serious 

 mistakes in judging the effects of treatments tried without proper 

 scientific checks. 



An effort is being made to get more detailed information regard- 

 ing the distribution of the Isle of Wight disease in France, as this 

 will help in determining how widespread the disease is on the Con- 

 tinent and will permit one to form some idea of the possible dura- 

 tion of the outbreak and the probability that the mite is also found 

 in adjacent countries of Europe. 4 



Several of the statements that have been made regarding the dis- 

 ease in France assume that it is less virulent there than in England. 

 To what extent such statements may be accepted is uncertain, and, if 

 such a difference exists, it may be due to the condition described by 

 Morgenthaler (44) and discussed on a later page of this circular 

 (p. 18). Possibly some of this opinion is due to an overestimation 

 of the losses in Great Britain which naturally arose from the reading 

 of some of the articles from that country which appeared before the 

 cause of the disease was known. Those reporting the supposed dif- 

 ference between France and England do not record whether they 

 have seen cases of the disease in Great Britain. 5 



THE DUCHEMIN MITE. 



In the article by Giraud (28) reference is made to the finding by 

 Emile Duchemin in France in 1866 of a mite on the exterior of dead 

 bees and also on the sunflower, Helwmbkus cm/mms. This mite was 

 mentioned by Rennie (50, p. 776) in the first announcement of the 

 discovery of Acarapis icoodi. Since this finding and the references 



4 In a recent private communication (Apr. 3, 192:>), M. Lucien Borland, of the Museum 

 Nationals d'Histoire Naturelle. Paris, who made the first determinations of the mite 

 from the French Alps (p. 12), writes that the disease exists throughout the territory 

 of France, not continuously, but widely distributed, He states: "It appears to me 

 probable that the disease exists throughout Europe." Ho calls attention to the fact 

 that the disease is not easily spread, for all the colonies in an apiary are not attacked;. 

 !'o has nut found the condition which Morgenthaler ( //. )/) describes of the mite Indis- 

 tinguishable from Tarson-emus woodi on the outside of bees. He does not believe that 

 the spread of the disease in France is of recent occurrence. 



' A recent letter (Apr. L'2. 1923) from a prominent British beekeeper states that early 

 ;.: that month he imported some bees from mar Marseilles and that the bees of one 

 colony began to crawl in a few days after they were received. Examination of the 

 trachea? showed them to bo crowded with young parasites, but the tracheal trunks were 

 not yet stained. " I am of the opinion that English boos would not crawl at this stage. 

 The possibility of a very severe outbreak in this region [Marseilles] is greaU" 



