302 STATE BOARD OF AGRICULTURE. 



tinguishing European foul-brood. Larvae which are older than four days 

 commence to stretch out in the cell as room for growth is required, and when 

 attacked at this period will be found dead in a sort of a cork screw position. 

 Sometimes the larvae are attacked after they have stretched out in the bases 

 of the cells, but this is not the general rule. The scales are not adhesive to 

 the walls of the cell as are the scales of American foul-brood, and can be re- 

 moved by the adult bees. Furthermore, diseased larvae which have not 

 dried down in the scale are sometimes removed by the adult bees in piece- 

 meal. 



METHODS OP SPREAD OP THE DISEASE. 



European foul-brood is spread from diseased to healthy colonies by means 

 of the transmission of infected honey or other diseased material. The rob- 

 bing of diseased colonies by healthy ones is probably the most frequent 

 method of spread. The interchanging of combs of brood from diseased to 

 healthy colonies also transmits the disease. It is possible that nurse bees 

 from the diseased colony may carry the virus on their mouth parts and body, 

 thus infecting healthy larvae in feeding them. It is also probable that oc- 

 casional nurse bees from diseased colonies return to healthy colonies after 

 play flights, carrying diseased material. This has not been definitely proved. 

 As the virus lives in honey about 7 months there is slight danger of infection 

 from feeding honey which has been carried over winter. Dry extracting 

 combs which have contained honey from a European foul-brood colony 

 would probably transmit the disease to brood reared in those combs. How- 

 ever, as the virus lives for a shorter period of time in the scales and honey 

 than the virus of American foul-brood, the European is more easily controlled. 



TREATMENT. 



The method of treatment of European foul-brood will depend upon the 

 progress the disease has made in the colony, the race of bees, the strength of 

 the colony and the honey flow. It is known that Italian bees resist European 

 foul-brood better than other races, probably due to their superior ability as 

 house cleaners. It is also known that European foul-brood is a disease of 

 weak colonies principally and will usually disappear in the colony with the 

 arrival of a good honey flow. If the disease has not made considerable pro- 

 gress in the brood-nest by the time the treatment is given it is advisable to 

 allow the bees to clean up the diseased combs. If on the other hand a very 

 large percentage of the brood nest is diseased it is questionable whether it 

 is best to force the bees to clean up the diseased combs or whether the colony 

 should be shaken on to full sheets of foundation and given a young laying 

 queen of resistant Italian stock. If the bees are to be forced to clean up the 

 disease the following method is followed: First, make sure that you will 

 have a young laying Italian queen available two weeks from the time the 

 treatment is given. Kill the queen in the diseased colony, and if the diseased 

 colony is weak in bees double enough diseased colonies together to make 

 strong colonies. Allow these colonies to remain queenless for from ten days 

 to two weeks, then introduce the young laying queen of resistant Itahan 

 stock. If the attack is mild and the colonies are already of pure Italian 

 stock it may be desirable to cage the queen for ten days instead of killing 

 her. Dr. Miller used this method successfully. If the queen is old, and 

 especially if she is not Italian, it is always best to kill her. The period of 

 time that the colony remains queenless will depend upon the length of time 



