BEES IN COLONIES AFFECTED BY EUROPEAN FOULBROOD 17 



SUPPLEMENTARY OBSERVATIONS 



STUDY OF NATURALLY INFECTED COLONIES 



As a supplementary study to the preceding artificial infection ex- 

 periments, some observations were made upon the behavior of nat- 

 urally infected colonies undergoing treatment. Through the kind- 

 ness of W. L. Bean, of McGraw, N. Y., it was possible to make a 

 series of such observations. In his apiary of about 30 colonies, all 

 hybrids, the majority were diseased when observed June 8, 1918. 

 Soon thereafter Mr. Bean kindly loaned two of these diseased colo- 

 nies to be carried to Ithaca for closer observation. Mr. Bean at 

 once started treating his bees, requeening with Italian stock by the 

 method of introducing a queen cell almost ready to emerge. Appar- 

 ently, this method was successful, for in the latter part of July Mr. 

 Bean reported all treated colonies healthy and some 800 pounds of 

 surplus honey. 



COLONY J 



Race. — Hybrid. 



Queen. — Queenless at time of arrival at Ithaca, Was poor hybrid of own 



raising, probably reared while disease was present in the colony. 

 Strength in spring. — Weali. 

 Strength at time of treatment. — Scattered brood in eight frames. Weak 



in bees, particularly in nurse bees. 

 Approximate date of disease first noted. — May 31, 1918. 

 Date of start of treatment observations. — June 16, 1918. 



This colony made no effort to clean up, even though, tliey had lost 

 their queen shortly before being brought to Ithaca. On the 18th of 

 June six frames of Italian bees and emerging brood were placed on 

 top of it. At once house cleaning started, a reduction, of 50 per cent 

 being noted in the fresh, moist, melting larvae within 24 hours. In 

 this colony it was interesting to watch the bees doing the house clean- 

 ing, particularly when diseased larvae in various stages of decomposi- 

 tion were partially withdrawn from the cell with a pair of forceps. 

 With the aid of a powerful hand magnifying glass it was easy to 

 watch them suck up the juices of the dead larvae, even those which 

 had decomposed to the extent of being a coffee brown in color and 

 viscid in consistency. No bee would work long on a larva but would 

 back off and wipe her tongue thoroughly with her front feet. It is 

 conceivable that this might contaminate her, making possible car- 

 riage of the infection to the next larva fed, even though the juices of 

 the diseased larva were not actually fed to the healthy one. The 

 majority of bees engaged in this work were the Italians. From these 

 and other observations of a similar nature there is no doubt that the 

 contamination of the mouth parts is the primary method of spread- 

 ing the disease inside the colony. 



