CORNELL UNIVERSITY LIBRARY wi BPECIAL BULLETIN 64 JANUARY, 1914 \ een ro Seed : o oma eA MICHIGAN STATE AGRICULTURAL COLLEGE EXPERIMENT STATION DIVISION OF ENTOMOLOGY —_—_ “ EQUL BROOD SUPPLEMENT TO SPECIAL BULLETIN 58 F. E. MILLEN EAST LANSING, MICHIGAN 1914 tS p l @. SF eee | 5 Flog M v4 F OIF SPECIAL BULLETIN 64 JANUARY, 1914 SUPPLEMENT TO SPECIAL NO. Bs. BY FP. E. MILLEN, STATE INSPECTOR APIARIES. INTRODUCTION. Since Special Bulletin No. 58 was published, additional knowledge, concerning European foul-brood, has been gained. A third brood-dis- ease, S Sacbrood, has also been identified and | is dealt with in the follow- ing pages. Also the new law déaling with Inspection of Apiaries, passed during the Legislative Assembly of 19138, is incorporated in this supplement. SACBROOD. beside two foul-brood diseases,—American foul-brood and Euro- pean foul-brood, there is a third brood disease known as Sacbrood be- lieved ta be caused by a filterable virus.* Older beekeepers will recognize this disease as pickled or sour-brood, since it now seems likely that most or all cases of pickle brood are really Sacbrood. While this disease is infectious, usually it is not severe enough to re- quire treatment in the general run of apiaries producing honey alone. Any bee-keeper in Michigan who suspects the presence of foul-brood in his or in his neighbor’s apiary should notify the State Inspector of Apiaries, Department of Entomology, Michigan Agricultural Conese rast Lansing, Mich. LOSSES CAUSED BY BROOD DISEASES. The name, “brood disease,” at once conveys the information that it is the brood which suffers. We know that the life of a worker honey-bee is short, and that dur- ing a heavy honey-flow the active part of its life is shortened to a few weeks, so that there must be a very heavy daily mortality through the summer sedson. The cleanly habits of the bees prevent the bee-keeper from noticing this loss, because the workers carry nearly all the dead bees away from the entrances, and then too, a very large number die in the field. In a normal, healthy colony with a vigorous queen this heavy loss passes unobserved, since the queen, capable of laying two- thousand or more eggs daily, easily keeps up the population of the hive. Directly foul-brood enters a colony the young larvae (worms) or (grubs) are attacked, and if the disease becomes serious, there may be as high as 90% of the larvae killed; thus in the place of the bees hatching daily by the thousand there may be only a few dozen. At * Circular 169, Bureau of Ent., U.S. Dept. of Agr., Dr. G. F. White. 4° EXPERIMENT STATION BULLETIN. the same time, the adult bees are dying off naturally and in a few weeks we find a very poor colony where there was formerly a strong one. ; The damage done by foul-brood then is serious because it means not only a loss of the honey crop together with the increase in colonies, but if neglected a total loss of the apiary. TREATMENT FOR EUROPEAN FOUL-BROOD. On page eight of Bulletin 58 is the heading “Treatment for both in- fectious diseases.” This should be read “Treatment for American foul-- brood.” The treatment for European foul-brood is similar, but does not end with the shaking treatment alone. The following treatment is recommended for European foul-brood. 7 Owing to the comparatively recent advent of European foul-brood, as well as to its more scattered occurrence, our knowledge of its na- ture and treatment is less accurate and we have to do our work with less of confidence and certainty than in the case of the more familiar American foul-brood. The most satisfactory results of all, in our experien@ hfW resulted from following the plan, herein set down. : The first part of the treatment for this disease is the same hat out- lined for American foul-brood, but it does not end there. To make the treatment effective, the shaking must be followed by requeening the entire apiary with pure queens of some race not black. The gen- eral experience of bee-keepers thus far has been more or less confined to the Italian race, and for this reason we recommend Italians, al- though other races may prove their value for this purpose on trial. Even when one has gone this far he is not safe from the ravages of Euro- pean foul-rood, unless he is constantly requeening all colonies that show impurely mated queens or queens of poor constitution. The secret of successfully fighting this disease seems to be largely in the improve- ment of the virility of the bees, thus eliminating all but strong colonies: Feeding up heavily in the Fall with sugar syrup,-and stimulating feed- ing in the Spring, between flows, also helps in keeping down the virulence of the disease. ; SACBROOD. This disease shows some symptoms that resemble both those of the American and of the European foul-brood,—the sunken, discolored and perforated cappings resemble those found in American foul-brood, while some larvae are extended and flattened like those dead from European foul-brood. Sacbrood differs from American foul-brood in that ropiness and the gluey smell are lacking, and the dead larvae usually can be taken from the cells without breaking their skins. It differs from European foul- brood in the lack of odor, and it never has that greasy melted appear- ance so typical of certain stages in European foul-brood. The symptems vary in the same hive, some of the dead larvae are extended and fiattened in the cell, with black spots on the head. These usually lose their segmented appearance to a large extent. Again other FOUL BROOD. 5 larvae, while extended, have a more or less rounded shape, with the segmentation of the body well marked. *“The brood dies after the time of capping. The dead larvae are therefore almost always found extended lengthwise in the cells and ly- ing with the dorsal side against the lower wall. It is not unusual to find many larvae dead of this disease in uncapped cells.” “Such brood, however, had been uncapped by the bees after it died. In this disease the cappings are frequently punctured by the bees. Oc- casionally a capping has a hole through it, indicating that the capping itself had never been completed.