DIAGNOSING BEE DISEASES IN THE APIARY 9 



is prominent. In advanced cases rows of cells contain dead larvae 

 uniformly in this position. 



When scales are numerous the disease can be diagnosed from their 

 appearance alone. Scales can be seen extended along the lower side 

 walls when the comb is held inclined so that a bright light falls on 

 the lower side walls and bottoms of the cells. Occasionally cross 

 markings which represent the segmentation of the larvae can be seen 

 on the scales. When completely dried the scales are brittle and ad- 

 here so tightly to the cell walls that it is difficult to remove a scale 

 without breaking it. When death occurs after pupation has started, 

 the form of the pupa can be recognized in the scale (figs. 3, Z7, and 

 4, F) . The mouth parts of the dead pupa may protrude from the head 

 of the scale and appear as a fine thread slanting slightly backward into 

 <he cell and at times adhering to the upper wall (fig. 3, F). The 

 appearance of protruding or "stuck up" tongues is one of the most 

 dependable symptoms of American foulbrood. 



ODOR OF THE DEAD BROOD 



In the first stages of decay, while the remains are still white, 

 practically no odor is detectable. When the remains begin to turn 

 brown and become ropy, however, an odor develops that is different 

 from the typical gluepot odor characteristic of the advanced stages 

 of this disease. In later stages, when the dead brood is brown and 

 decidedly ropy, the familiar gluepot odor is always present, but 

 it practically disappears when the scales are completely dry. In 

 advanced cases, when much decaying brood is present, the gluepot 

 odor can be detected even a foot or more from the combs. Since 

 the odor of American foulbrood is characteristic, the use of the odor 

 test is of considerable value in the diagnosis of doubtful cases. The 

 odor can best be judged by holding some of the decayed remains on 

 a toothpick at the entrance to the nostril and breathing deeply. 



DIAGNOSTIC TEST 



In case the typical symptoms of American foulbrood are not present, 

 or further confirmation is desired, it is advisable to run the "milk 

 test," which is specific for this disease. 



The test is based on the presence of enzymes in the dead larvae, 

 both in the ropy and scale stage, which liquefy the casein or curd in 

 milk. These enzymes are produced by Bacillus larvae as it grows and 

 forms spores in the larva. 



Materials needed for the test are a 1-dram homeopathic vial, a 

 medicine dropper, and skim milk, either fresh or the powder. The 

 powder should be used when a large number of tests are to be run. 

 It should be added to water at the rate of 1 level tablespoon per cup, 

 and shaken until the mixture is uniform, on the day the test is run. 

 Various types of water have been used, with no unfavorable results. 

 However, if there is any doubt about the water, another test can be 

 run with distilled water and the results compared. Best results are 

 obtained if the water is warm but not uncomfortably hot, although 

 the test will work around 50° F. At the low temperatures somewhat 

 slower clearing can be expected. 



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