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GLEANINGS IN BEE CULTURE 



June, 1920 



Books and Bulletins 



Bulletin No. 809, "American Foul Brood," 

 by G. F. White, is based upon observations 

 made in the laboratory and in the experi- 

 mental apiary, and is for the practical bee- 

 keeper as well as those who wish to make 

 further study of the disease. The bulletin 

 discusses the resistance of Bacillus larvae 

 to various destructive agencies; the effect 

 of the disease on the colony; and the trans- 

 mission and diagnosis of the disease. 



A general description of the symptoms 

 and a detailed and well-illustrated de- 

 scription of the exact appearance of the 

 dead larvae and also of dead pupae during 

 the five stages of the disease, make the bul- 

 letin of value to all beekeepers. 



This disease, as has been known for some 

 time, is caused by Bacillus larvae and is a 

 disease of the brood and not of the adult 

 bees. Mr. White has proved that all worker, 

 drone, and queen larvag are susceptible to in- 

 fection, but he has not been able to produce 

 infection in other insects or in animals. 



The colonies on which he experimented 

 were fed spores of the Bacillus, the infec- 

 tion taking place along the alimentary 

 tract. He found that the incubation period 

 is approximately seven days and that in 

 about one month, after a heavy inoculation, 

 the colony becomes weakened, but is not 

 destroyed by the disease for three months or 

 longer. Mr. White says that it is very rarely 

 that any even slightly affected colony ever 

 recovers from the disease without treatment. 

 Altho the brood is susceptible to infection 

 at all seasons, the disease is more severe 

 during the second half of the brood-rearing 

 season than during the first half. Neither 

 the climate nor the quality or quantity of 

 stores appears to affect the disease much. 



The spores of American foul brood in 

 scales, he found, sometimes remain virulent 

 for years. They are very resistant to most 

 destructive agencies. The most resistant 

 spores when in water withstand 212 degrees 

 F. for 11 minutes, and when in honey with- 

 stand the same temperature for half an 

 hour. Sunlight destroys dry spores in 28 

 to 41 hours, and spores in honey in from 4 

 to 6 weeks. When shielded from sunlight, 

 spores in honey remain virulent for over 

 a year. Spores resist fermentation and vari- 

 ous drugs a long enough time to indicate 

 that hope of treatment probably does not lie 

 in this direction. 



It is possible, Mr. White states, that the 

 disease is sometimes transmitted thru the 

 water supply, but the primary means of 

 transmission is thru the stores, especially 

 thru the robbing of diseased colonies and 

 sometimes thru the placing of diseased 

 combs in healthy colonies. 



He does not consider flowers a medium for 

 transmitting the disease, nor does he think 

 there is much danger from tools, bee sup- 

 plies, clothing, or hands. Even hives that 

 have contained diseased colonies, he saTs, 



do not always transmit the disease, altho 

 he advises flaming out the insides of the 

 hives to make them safe. 



It is our sincere hope that none of our 

 readers will get the idea that American 

 foul brood is not as easily transmitted as 

 they had believed, for it is certain that the 

 disease is readily transmitted by any medi- 

 um that is contaminated with diseased hon- 

 ey. Elsewhere in the bulletin we find a 

 statement that the likelihood of the disease 

 being transmitted by combs from diseased 

 colonies is probably frequently overestimat- 

 ed, and that such spreading of the disease 

 probably depends considerably upon the 

 amount of infection in the colony from 

 which the comb was taken and also, to some 

 extent, upon the presence or absence of 

 brood in the colony to which the combs are 

 given. Suflicient facts, it is asserted, are 

 wanting to make definite statements in re- 

 gard to the probability of infection in such 

 cases. From our own experience as well 

 as that of others, we believe that combs 

 from diseased colonies often contain diseas- 

 ed honey, and that they are always a source 

 of danger if any of the cells have ever con- 

 tained diseased larvae. If a beekeeper is 

 really anxious to get rid of the disease, we 

 do not think it will pay him to take chances 

 in using combs from diseased colonies. 

 Again, Mr. White says that colonies in 

 which the disease has been produced thru 

 artificial inoculation can be kept in the ex- 

 perimental yard without transmitting the 

 disease to other colonies, and he believes 

 this fact of importance in the control of the 

 malady. In actual practice there are so 

 many accidents that might happen to an 

 infected colony which would allow other 

 colonies access to the diseased honey, that it 

 is safer to move all such colonies to a hos- 

 pital yard for treatment. 



Another new government bulletin, No. 

 1084 is "Control of American Foul Brood," 

 by E. F. Phillips. This short pamphlet, al- 

 tho it gives no new developments, sums up 

 the vital facts of importance to the practi- 

 cal beekeeper in the treatment of American 

 foul brood. All beekeepers will find valua- 

 ble advice in this bulletin, as "Never feed 

 honey purchased on the open market"; and 

 ' ' In introducing purchased queens, transfer 

 them to clean cages provided with candy 

 known to be free from contamination, and 

 destroy the old cage, candy, and accompany- 

 ing workers." Also, when speaking of us- 

 ing extracting combs from diseased colonies 

 he fully sizes up the situation from the 

 standpoint of the producer when he says: 

 "The saving of such combs, however, is ex- 

 tremely dangerous, and such a policy is not 

 to be advised. The beekeeper who takes 

 all the precautions which it is possible to 

 take, is the one who most quickly and cheap- 

 ly eradicates American foul brood from his 

 apiary. ' ' 



Apply to Division of Publications, U. S. 

 Dept. of Agriculture, Washington, D. C, 

 for the two bulletins referred to above. 



