SACBTtOOD. 



33 



broken up, preferably by trees or shrubbery. By these means, it 

 will be observed, there is a tendency to minimize the likelihood of 

 robbing, swarming, absconding, and accidental straying or drifting 

 of bees to foreign colonies. 



In preparing the material with which the colony is inoculated, 

 larvse in early stages of the disease are picked from the brood 

 frames, crushed, and added to sugar sirup. The 

 crushed mass from 10 or more sacbrood larvse, sus- 

 pended in somewhat more than half a pint of sugar 

 sirup, has been found to be a suitable quantity of the 

 infective material to use in making an inoculation. 

 The suspension may be fed to the bees as one feeding 

 or more. The inoculation feedings should be made as 

 a rule toward evening to avoid the tendency to rob, 

 which may be noticed during a dearth of nectar. Inocu- 

 lations should not be made when the tendency to rob 

 is at all marked. 



Before a colony is inoculated it should be deter- 

 mined that its activities are normal. A colony should 

 not be inoculated for several days after it has been 

 made by division, or immediately after its removal 

 from a foreign location. An experimental colony when 

 inoculated should have larvse of all ages, and a queen 

 doing well. 



Between five and six days after a colony has been 

 inoculated with sacbrood virus, the first symptoms of 

 the disease are to be expected. The finding of capped 

 larvse having a slightly yellowish hue (fig. 12; PI. II, 

 h, h) is the best early symptom by which the presence 

 of the disease may be known. 



Another method of inoculation may be used and 

 under certain circiimstances is desirable. The method 

 is more direct than the one just described. The 

 crushed tissues of a diseased larva are suspended in a 

 small amount of water or thin sugar sirup. With a 

 capillary pipette (fig. 30) made from smaU glass tubing, 

 a very small amoimt of the suspension is added di- 

 rectly to the food which surrounds the healthy larva 

 in the cell. This is easily done. Having drawn some of the suspen- 

 sion into the pipette, carefully touch the food iu the ceU surround- 

 ing the larva with the point of the pipette. A small amount of the 

 suspension will flow out and mix with the food. Larvse approxi- 

 mately two days of age should be selected for feeding. A dozen 





Fig. 30— Capillary 

 pipette. A piece 

 of glass tubing 

 drawn to capil- 

 lary size at one 

 end. Keduced to 

 three-fourths of 

 the size nsed. 

 (Original.) 



