Sept. 1, 1932 Commercial Honey and Spread of American Foutbrood 253 



close proximity to the apiary connected with the laboratory and tO' 

 other privately owned colonies of bees, necessitating extreme pre- 

 cautions to prevent spread of the disease. In 1927 the experimental 

 work was transferred to the Intermountain States bee culture field 

 laboratory at Laramie, Wyo.* In Wyoming an ideal isolated location 

 was foimd about 14 miles east of Laramie in the Medicine Bow Na- 

 tional Forest, the nearest colonies of bees being at least 14 miles away 

 and probably farther. Since this location is more than 8,000 feet 

 above sea level, there is only a slight nectar flow from wild flowers, 

 which assures the immediate use of any inoculated simp fed to colonies 

 of bees. In fact, after the middle of the summer it was found neces- 

 sary in most cases to feed the experimental colonies with uninocu- 

 lated sugar sirup in order to prevent starvation. 



In 1927 and 1928 the colonies used for experimentation were located 

 in two yards between a quarter and a half mile apart. The arrange- 

 ment of the colonies in the two yards was such as to prevent drifting' 

 as rnuch as possible. In 1929 and 1930, in order to limit still further 

 the danger of transmission of disease because of drifting or robbing,. 

 20 colonies were stationed in pairs, so arranged as to minimize the 

 danger from drifting, in 10 isolated locations at least a quarter of a. 

 mile apart. 



Make-up of Colonies 



Five-frame nucleus hives were used for the spore-feeding experi- 

 ments. The colonies were prepared either with two or three frames, 

 of brood, honey, and adhering bees taken from healthy colonies, 

 together with a young laying queen, or, as in 1927, 1928, and 1929, 

 by placing a 2-pound package of bees containing a laying queen on 

 foundation or on combs containing honey from healthy colonies and 

 feeding them sugar sirup. During a good honey flow these small 

 colonies were allowed to build up in the apiary connected with the 

 laboratory until they consisted of three or four frames of brood before 

 they were moved to the isolated locations. The bees making up the 

 colonies used for the feeding experiments from 1927 to 193Q at Lara- 

 mie, Wyo., were all from the same general strain. 



Material Used for Inoculation 



Spores of Bacillus larvae were obtained from American foulbrood 

 scales in combs taken from diseased colonies located in the States of 

 Maryland, Iowa, and Wyoming. The strain used at Somerset, Md., 

 was obtained from a sample sent to that laboratory for diagnosis. 

 Two different strains were used at Laramie during 1927, 1928, and 

 1929, one obtained from a diseased colony in the experimental apiary 

 belonging to the University of W^yoming and one obtained from a bee- 

 keeper at Lander, Wyo. In 1930 three other strains were used in 

 the feeding experiments, one from Iowa and two from apiaries in 



Wyoming. 



Preparation of Spore Suspensions 



In preparing the spores for feeding to the healthy colonies, scales 

 were removed from the combs by means of sterile forceps (the neces- 

 sary precautions being taken against contamination) and placed in 



< This laboratory is maintained cooperatively by tbe University of Wyoming and the U. S. Department 

 of Agriculture. 



