4 TECHNICAL BULLETIN 149, TJ. S. DEPT. OF AGKICULTTJRE 



Link, found on mummified bees in Germany, was able to infect capped 

 and uncapped brood and adult bees by artificial inoculation with the 

 first two. T. Ugnorum was shown to be capable of becoming actively 

 pathogenic when introduced into healthy colonies on brood combs. 

 When similarly introduced, M. rrmoedo attacked and killed brood in 

 capped cells and an occasional adult bee. In his experiments with 

 P. glaucum neither the bees nor their brood were attacked, although 

 it is one of the commonest organisms in the hive. 



While making anatomical studies of honeybees affected with con- 

 stipation, Lardinois {17) claims to have observed SaccharoTnyces 

 apiculat-ws (Reess) Hansen constantly associated with lesions in the 

 tissues. The same organism occurred in the intestines of dead pupae 

 that were thrown out of the hive, in the food of larvae, and in honey. 

 Lardinois asserts his belief that S. apicwlMvjs is the sole cause of May 

 disease and that disturbances commonly recognized as constipation, 

 paralysis, convulsions, staggering, malformation, and death of brood 

 are, in reality, all forms of the disease which he called saccharo- 

 mycosis. He does not support these conclusions by inoculation ex- 

 periments but draws them solely from the fact that this yeast occurs 

 in " lesions " and in the intestine of bees affected with " May disease." 

 Doctor Lardinois believes, however, that these conclusions may be 

 easily verified. 



One is quickly led to believe that bee diseases caused by pathogenic 

 fungi may be more widespread than is commonly supposed. A com- 

 parison of conditions in Euro^De^ where a number of recognized fungi 

 are known to cause diseases of bees, with conditions in this country 

 would make it seem likely that the same fungi are capable of attack- 

 ing bees here. The publications of Thom and Church {2J^; SS, 

 p. 200) show that a great number of strains of Aspergillus f,avus 

 are found in America. Mucor mvicedo and Triohoderma ligrvorwin 

 also occur elsewhere than in Europe. Perioystis apis and P. cil/aei 

 Betts, which, according to Claussen {8), differ in certain morpho- 

 logical characters and in their ability to attack brood of bees, have 

 never been reported from North America. Forms of Saccharomyces 

 apiculatus, which Lardinois has stated cause disease of bees in France, 

 are widely distributed in North America. The writer has frequently 

 found these forms in North America within the alimentary canal of 

 bees and in honey. 



INVESTIGATIONS WITH PATHOGENS 



DESCRIPTIONS AND LOCATIONS OF APIARIES USED 



Apiaries located in the vicinity of Bronson, Mich., were used in 

 these investigations for securing specimens of fungi and for making 

 tests for pathogenicity and control. These apiaries are situated on 

 boulder clay and sandy drift formations in a general farming com- 

 munity. Three honey flows occur annually in the region, providing 

 a plentiful supply of stores at all times when weather conditions are 

 favorable. 



The experimental apiary of the botanical laboratory of the Uni- 

 versity of Michigan at Ann Arbor was also used in these investiga- 

 tions. This apiary was located on the roof of the Natural Science 

 Building, thus affording excellent conditions for recovering diseased 



