File:American bee journal (1920) (17926316618).jpg

Title: American bee journal
Identifier: americanbeejourn6061hami (find matches)
Year: 1861 (1860s)
Authors:
Subjects: Bee culture; Bees
Publisher: (Hamilton, Ill. , etc. , Dadant & Sons)
Contributing Library: UMass Amherst Libraries
Digitizing Sponsor: UMass Amherst Libraries

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1920 AMERICAN BEE JOURNAL 227 served, the likelihood of robbing, swarming, absconding and accidental straying or drifting of bees is re- duced. In making the inoculations two methods were used. Those have been referred to as the direct and the in- direct methods, respectively. Follow- ing the direct method, a group of about 10 to 20 larva;, 2 to 3 days old, are fed thin sugar syrup to which has been added the contents of stomachs of sick larvse. This is done by put- ting a very small quantity of the con- taminated syrup directly with the food of the larva within the cell. For this purpose a small glass tube is used Care must be taken that too much syrup is not added in making the inoculations, as the larvae would be floated thereby. Care must be observed also that they are not disturbed mechanically by the tube. Disturbances of this kind are very likely to be followed by their re- moval by the adult bees. Within 3 days the inoculated larvae show marked symptoms of the disease, some of the sick or dead ones are re- moved by the end of the third day and most of them before the end of the fourth day. Only a few are found infected outside the arena of brood inoculated. The colony usually speedily recovers from the infection and no further evidence of the dis- ease is seen. By the indirect method the entire colony is inoculated through feeding it about one-third of a pint of sugar syrup to which the crushed bodies of from S to 10 larvae sick or dead of the disease have been added. The first symptoms of the disease are ob- served about 3 days after inoculation. The youngest larvae to show symp- toms are about 4 days old. After a single feeding the colony usually soon recovers from the disease. Other factors being equal, the recovery is more rapid when the amount of brood is small in proportion to the strength of the colony, when the flow of nectar is good, and when the bees are active. A stock of fresh disease material is needed during most of the experi- mental studies, and this can be se- cured from colonies inoculated for this purpose. In inoculating these stock colonies the disease material for the first feeding is taken from samples received from the beekeep- ers. Repeated inoculations are need- ed, as a rule, to keep the colony dis- eased, as there is a marked tendency for the colony to recover from the in- fection. The material for these sub- sequent inoculations is taken from the stock colonies themselves. For the first inoculation the direct meth- od is used, and for the subsequent ones the indirect method is em- ployed. It is only after repeated inocula- tions have been made and the disease has been in the colony for some time that the rubberlike scales (Fig. 5. R, T) are found that resemble in many ways those of American foulbrood. As these scales are somewhat diffi- cult for the bee to remove, the num- ber present naturally increases to a certain extent during the course of the disease. The number encoun- tered in any given area of brood- comb, however, is always small. The bees allow some of them to remain in the brood-comb for a considerable period. Some of the experimental colonies that were rather heavily infected, but which remained sufficiently strong to winter well, were found to be diseased in the spring, but some were not. Those that were only lightly infected, as a rule, did not show the disease the next year. Whether the germs used had previ- ously been in a diseased colony has given the writer no uneasiness. All hives which had housed a European foulbrood colony were flamed inside before they were used again. (To be Continued)
Text Appearing After Image:
J -W O Fig. 5. European foulbrood. A to M uncapped, and N to T capped brood; D. healthy larva at the earliest age at which symptoms of the disease appears; A E, young larvx showing symp- toms of European foulbrood: B O, larv*e partially removed by tlie adult bees; C, scales from young larva; F I, healthy larvae somewhat older than D. G H J, dead larvae of the same age as F and I; K, healthy larvx slightly older than F. with dorsal side turned toward the observer; L M, dead larv,i; about the same age as K; N, larva dead at the time of spinning: O, scale of a larva similar to N; P, a punctured cap; Q R S T, larva which had assumed the endwise position in the cell before death; Q. larva partially removed; S. lari'a dead of the disease; R T, end and ventral view, respectively, of European foulbrood scales of larva of the age shown in S. These scales and those of American foulbrood are quite alike. The caps from N O Q R S and T were removed by the adult bees.

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