Mav, 1922 



GLEANINGS IN B K E CULTURE 



active vegetative rods. This causes death, 

 as a rule, to occur later iu the life history 

 of the larva. Therefore the diseased larva 

 is found almost always to have been sealed 

 over before death occurred, having finished 

 spinning its cocoon and taken the flat ex- 

 tended position preparatory to pupation. 



In bad or virulent cases, however, it has 

 been noted that occasionally some coiled 

 larvae do die before extending in the cells. 

 These often have somewhat the appearance 

 of typical coiled European foul brood lar- 

 vae.' The reason for this is that these coiled 

 larvae incidentally have been fed some act- 

 ive vegetative rods instead of the slowly 

 germinating spores. Therefore, the rods are 

 able to start activities at once and thereby 



Fig. 2. — American foul brood, 

 a, b, f, normal sealed cells; c. 

 J j, s\inken cappings showing 

 perforations ; g, sunken capping 

 not perforated, often showing 

 glistening brown surface of co- 

 coon pressed inwards by cap- 

 ping; h, 1. m. n, q r, larvae affected by the dis- 

 ease in various stages of decomposition and dry- 

 ing down. Note that all lie uniformly extended in 

 practically the same position along lower side wall 

 of cell; e, i, p, s, gummy or brittle scales formed 

 from dried-down larvae; the anterior end may be 

 broken off occasionally and removed, but posterior 

 end curved up into the bottom of the cell remains 

 glued fast; o, pupa showing form of adult bee 

 affected by the disease, in first stages of decom- 

 position ; d, dried-down pupa with tongue extend- 

 ed, remaining attached to top wall of the cell like 

 a fine thread. 



cause the death of the larva much sooner. 

 Under the microscope the diseased coiled lar- 

 vae always show considerable numbers of 

 the vegetative rod forms and few if any of 

 the spores. 



The last-described manifestation is about 

 the only confusing variation in the syni]) 

 toms of American foul brood which might 

 be misleading to the beekeeper. The coiled 

 position and yellowish-brown color might 

 suggest European foul brood, but upon 

 closer examination the consistency is found 

 to be quite different. It is slimy, with a 

 tendency to rope like the typical American 

 foul brood larva, instead of having the 

 characteristic moist, melting, cheesy con- 

 sistency of coiled European foul brood. This 

 variation is a more or less rare occurrence 

 and should cause no trouble in the gross di- 

 agnosis of American foul brood, since the 

 combs will be well filled with the typical 

 forms of the disease. 



A Never Failing Positive Symptom of 

 American Foul Brood. 



There is one symi)tuMi in American foul 

 brood upon which a positive gross diagnosis 

 can be made when it is found. Occasionally 

 the action of lUicillus larvae in some of the 

 infected larvae is for some reason slower 

 than in the others, and, as a result, some 

 reach the pupal stage before death. They 

 may have started even to take the form of 

 the adult bee (Fig. 2, o). This does not 

 occur in large numbers but may be recognized 

 by the fine, thread-like tongue of the pupa 

 which was extended at time of death. It 

 usually -remains fastened to the upper side 

 wall, slanting slightly inward from the head 

 of the pupa (Fig. 2, d). This symptom 

 when found should aid the beekeeper great 

 ly in diagnosis of American foul brood. 



Both Diseases in the Same Colony. 



This brings the discussion down to occa- 

 sional cases of so-called mixed infection, 

 where both diseases are found in the same 

 colony. These have a more reasonable basis 

 for causing confusion and come more nearly 

 requiring a bacteriological examination. 

 Here, however, the colony as a whole must 

 be taken as a unit instead of the individual 

 larva. As far as is authentically known, 

 the organism causing European foul brood, 

 Bacillus pluton, has never been found in the 

 same larva with Bacillus larrae, the cause of 

 American foul brood. Individual larvae 

 may be found in the same colony affected 

 either by European foul brood and contain- 

 Bacillus pluton with associated secondarj- 

 invaders, or affected by American foul brood 

 with Bacillus larvae alone. Neither one of 

 these organisms is found as a secondary in- 

 vader to the other. The proof of this lies 

 in the fact that Bacillus larvar prevents the 

 growth of any other organisms after it has 

 once invaded the larva. Bacillus jilufou 

 would be unable to develop as a secondary 

 invader because of unfavorable growth con- 

 ditions produced by Bacillus larvae. If by 

 any chance Bacillus larvae were able to de- 

 velop as a secondary invader to Bacillus 

 pluton, which is not probable, Bacillus larvar 

 because of its vigorous growth and putre- 

 factive functions in the larva would destroy 

 Bacillus pluton before much chance of its 

 being detected even under the microscope. 

 In the 50 or 60 samples of mixed infection 

 found among several thousand samples of 

 brood diseases examined by the writer, 

 there has never been found any indication 

 of the presence of both organisms in the 

 same larva. 



Conclusions. 



The lesson to be drawn from this rather 

 hasty discussion of the problem of the dif- 

 ficulties of accurate gross diagnosis of the 

 brood diseases of bees, is one which every 

 beekeeper can take unto himself to a great 

 extent. Sufficient time should be taken to 

 study carefully all the symptoms and not 

 make a snap judgment on some one appar- 

 ent outstanding feature which may prove to 



