2C(5 



GLEANINGS IN BEK CULTURE 



May, 1920 



ease, the period of incubation, the symptoms 

 sliowii, the rate of increase, etc. 



The results of these experiments are ex- 

 ceedingly interesting. Bacillus pluton which, 

 as in previous experiments, was found to be 

 the primary invader, was noted in the in- 

 testinal tract of the larvae before death, in 

 fact with the first apparent symptoms. He 

 believes that the intestinal tract is the pri- 

 mary focus of infection, while the second- 

 ary invaders appear only after death and 

 are found mostly in the body tissues. 



The period of incubation was found to be 

 from 36 to 48 hours, altho the gross symp- 

 toms usually did not appear for three or 

 four days, the exact time depending on the 

 honey flow and the strength of the colony. 

 In eases in which colored syrup was given 

 the bees, in from 24 to 36 hours a number 

 of discolored larvae averaging four days old 

 could be seen, while the larvae younger than 

 three days never showed any discoloration. 

 This throws considerable light on the neces- 

 sary period of queenlessness when treating 

 European foul brood. 



During the first five to seven days after 

 infection the spread of the disease is slow, 

 but after that quite rapid if conditions are 

 favorable. The beekeeper should, therefore, 

 learn to detect the disease in its first stages 

 in order to treat it early. 



The disease is evidently spread in the 

 hives by the house-cleaning bees, and to oth- 

 er colonies by nurse bees drifting from one 

 hive to another. The infective organisms 

 are probably carried on the mouth parts 

 and feet. Under a magnifying glass the 

 nurse bees may be seen sucking up the juices 

 of the dead larvae, even those so decomposed 

 that they were a coffee-brown and ropy. 

 After working a short time on a larva, the 

 bee will back off and wipe her tongue thoro- 

 ly with her front feet. Mr. Sturtevant 

 thinks it likely that this might contaminate 

 her so that she would carry infection to the 

 next larva, even tho the juices of the dis- 

 eased larvae were not actually fed to the 

 healthy larvae. He believes the contamina- 

 tion of the mouth parts the primary method 

 of spreading the disease inside the colony. 

 When removing this affected material, he 

 noted the bees took it some distance from 

 the hive before dropping it. 



House-cleaning was carried on with more 

 energy by the Italians than by the hybrids, 

 and was especially rapid in the strongest 

 colonies. In one instance Mr. Sturtevant 

 noticed that the presence of a new queen, 

 tho still caged, gave an added impetus to 

 house-cleaning. The knowledge of this fact, 

 we believe, should be of practical help to 

 beekeepers in treating the disease. 



Italians were found to resist infection bet- 

 ter than hybrids and could more easily over-' 

 come the disease after being infected. This 

 resistance of the Italians he believes to be 

 largely due to their better house-cleaning 

 ha.bits rather than to a natural immunity. 



A heavy honey flow, he found, had a tend- 

 ency to prevent infection of a colony, and 



also to eliminate the disease if already 

 present. This, he says, is evidently on ac- 

 count of the dilution of the infected ma- 

 terial and the feeding of fresh nectar to the 

 larvae. 



Altho infection is not always entirely re- 

 moved by a period of queenlessness, it soon 

 disappears when enough young bees have 

 hatched to assist in the house-cleaning. Ex- 

 cept in the strongest Italian colonies that 

 are but slightly affected, requeening is nec- 

 essary, Mr. Sturtevant says, in treating 

 European foul brood. And under average 

 conditions, it is unsafe to allow less than a 

 ] 0-day period of queenlessness because of 

 the infectious condition of the diseased ma- 

 terial remaining. The confirmation of this 

 one fact alone is of considerable value to 

 beekeepers thruout the country in their fu- 

 ture treatment of the disease. All beekeep- 

 ers are greatly indebted to Mr. Sturtevant 

 for the new light he has thrown on the dis- 

 ease and also to the department that has 

 made his work possible. 



This bulletin may be obtained from the 

 Superintendent of Documents, Government 

 Printing Ofiice, Washington, D. C, at 5c 

 per copy. 



O l -l O ^ CM K 3 



AS SOME of our readers perhaps know, E. 



E. Eoot has just completed a trip of 8,000 



miles over the 



Changes in 



Honey-producing 



Areas. 



United States, go- 

 ing from coast to 

 coast and from 

 north to south. 

 While he has been over this territory sev- 

 eral times before, this time he took a rapid 

 survey, checking up the changes and the 

 regional differences in the United States so 

 far as they relate to honey plants and bee 

 territory. 



Conditions thruout the country east of 

 the Mississippi are about the same as for 

 years back; but winter losses in the North 

 may cut down the yield this year, no matter 

 how good the season may be. In the West, 

 rapid changes, as given in our April issue, 

 page 202, have taken place on account of 

 the onward march of sweet clover thruout 

 the Arkansas Valley, the Eocky Mountain 

 regions of Colorado, Wyoming, Montana, 

 and Idaho. 



The last-named territory will furnish 

 about the usual crop of alfalfa and sweet 

 clover — about an equal amount from each. 

 xMontana and Wyoming are coming to the 

 front very rapidly as bee States. 



The early cutting of alfalfa in the West 

 just as it comes into bloom (a practice that 

 is almost universal now) has been made up 

 and more than made up by the continuous 

 blooming of sweet clover, which is now be- 

 ing grown as a pasture crop where alfalfa 

 won 't grow. 



The East should understand that much of 

 tho alfalfa from the West in the last few 

 years has been about 50 per cent sweet 

 clover. Nor does this hurt it any; for in 



