1910 



GLEANINGS IN BEE CULTURE 



753 



General Correspondence 



EUROPEAN FOUL BROOD. 



Some Characteristics of the Disease; is it Possi- 

 ble to Cure by Six Days of Queenless- 

 ness? 



BY DK. C. C. MILLER. 



In the course of last summer I gradually 

 fell into a theory as to the workings of Eu- 

 ropean foul brood, which I here give for 

 what it is worth. The disease is conveyed 

 by means of bacilli — only in rare cases by 

 nieans of spores. When a larva becomes 

 infected, it dies when three or four days 

 old. It may die younger, and in some cases 

 it does not die till after it is sealed. As 

 soon as a larva dies, the bees may start to 

 remove it, or it may be left until it dries 

 down into a scale. If they begin to remove 

 it as soon as it dies, the juices of the dead 

 larva are so little affected by the disease 

 that they are still pleasant to the taste of 

 the nurse bee; she licks them up, just as 

 starving bees suck up the juices of unsealed 

 larviB, and when she feeds the next larva it 

 gets a dose of the bacilli and is doomed. If 

 a larva that has died from the disease is not 

 torn open very soon after death, it then be- 

 comes offensive, and its juices will not be 

 licked up. It will dry up into a scale, and 

 will then be carried out, but there will be 

 no continuance of the disease from that 

 scale, for the bee that carries it out does not 

 eat any of it, and so can not feed any of it 

 to a larva. If a larva is sealed before it dies, 

 no disease will come from it; the dried-up 

 larva will merely be carried out later on. 

 The rule is that the disease is continued 

 only from unsealed larva^ that have lately 

 died, perhaps within 24 hours of their death. 

 There may be exceptions. Occasionally a 

 spore may get into the food of a larva; but 

 bees don't make a practice of going about 

 hunting up filth to feed to their babies. At 

 the table of the neatest cooks in the world 

 you may occasionally get a hair in your 

 mouth; but neat cooks do not make a prac- 

 tice of serving up hairs by way of dessert. 



There's the theory. Please remember 

 that it's only theory. I don't k7iow that it's 

 true; but facts as I have observed them fit 

 in well with the theory. 



Let us see how the theory works out. We 

 will remove the queen of a diseased colony, 

 say June 1. All the brood will be sealed by 

 June 9 or 10, and at or after that date there 

 will be no diseased larva? with juices that a 

 nurse-bee would relish. So no larva will re- 

 ceive infected food if it is hatched from the 

 egg as late as June 10, and the disease will 

 cease to be. But if a larva hatches from 

 the egg June 10, that egg must be laid June 

 7. So if the queen is removed June 1, and 

 the same or another queen given June 7, a 



cure will be effected. In other words, six 

 days without any laying makes a cure. 



When I reached that point I said, " If that 

 theory is true, all that is needed is to cage 

 the queen for six days, and the colony will 

 be healed. Let's try it." It was then well 

 on in August, and I had only two diseased 

 colonies on which to experiment. One of 

 them was No. 105, which had a queen of 

 the previous year. I caged the queen Aug. 

 24, and freed her Aug 30. Eight days later 

 only clean brood was to be found in the 

 hive. No. 67 had been a diseased nu- 

 cleus, to which, by way of experiment, I 

 gave a virgin which I found laying July 19. 

 It continued diseased, in accordance with 

 Mr. Alexander's insistence that a colony 

 must be strong in order to be cured. Aug. 

 23 it had some brood in each of three frames, 

 an I was in pretty bad case. I gave it five 

 frames of brood with adhering bees, and 

 caged its (jueen. Aug. 29 I let the queen 

 out of the cage, and ten days later I found 

 the brood all clean. 



Please understand that I don't recom- 

 mend caging a queen six days as a cure. I 

 did that only as an experiment, and would 

 much rather have a vigorous young queen, 

 for a queen that has lived for some time in 

 a foul-broody colony generally has a logy 

 appearance, and is not so good as she ought 

 to be. She may not be diseased, and I do 

 not believe she would give the disease to 

 another colony; but she is the worse for her 

 experience, and is no longer up to the mark. 

 I have, however, great faith that a cure 

 may be expected if the old queen is killed, 

 and six days later the colony receives a lay- 

 ing queen that is young and vigorous. In 

 the two cases I have mentioned, the six 

 days of queenlessness proved sufficient to 

 effect a cure in spite of the retention of the 

 old queens. 



If six days' queenlessness cures, then 

 there ought to be no trouble about curing 

 by killing the old queen and giving a cell 

 or a virgin at the same time. It is possible 

 that five days of queeenlessness might an- 

 swer, and I believe a good many cures would 

 occur from three days of queenlessness. 

 Even a single day without eggs ought to be 

 some help, for we know that a little of the 

 disease will be cleaned up by a strong colo- 

 ny without any queenlessness. 



It is not hard to believe Mr. Green 

 when he says that a large percentage of 

 cures occur from merely changing queens, 

 for there is always some break in brood-rear- 

 ing upon the introduction of a new queen. 



I think I hear some one say: "But if your 

 theory be correct, then no case should last 

 over winter, for surely bro xl-rearing stops 

 more than six days in winter." Well, are 

 you sure that no mild cases are cured in 

 winter? And doesn't every case have a big 

 setback? If every case started in full blast 

 in the spring, just as it was the previous 

 year, wouli there be enough healthy brood 

 left to continue the colony throughout the 

 season? And with millions of spores left in 

 the hive, is it at all strange that some of 



