CHAPTER XI
Diseases of Bees
To understand thoroughly the life of the bee as exhibited in the hive is all to the benefit of the bee-keeper; for he will then quickly appreciate when matters are at all wrong with the bee communities in his care. He realises the necessity for keeping his stocks up to their full strength, for his knowledge tells him that they are better in every way for being numerically strong; they then keep warmer, consume less food proportionately than when the hive is weak, and give a far better return in brood and honey.
There are many infectious diseases to which bees are liable, most of which are due to bacilli and yeasts or ferments, and which receive untold assistance from inferior or fermenting food and unclean conditions in the hive.
These, then, are two conditions against which the good bee-keeper is always on guard. He is careful never to give fermenting honey, or an excess of artificial pollen, when natural food is scarce, and especially to bar unsuitable food such as beet, raw or ill-conditioned sugar, and syrup.
He is scrupulous concerning the cleanliness of the hives, and allows no accumulations of wax, dirt, dead bees, or the presence of decaying matter of any kind. Most particular is he, too, to see that the roofs are thoroughly watertight, for he knows that any leakage is bound to engender mildew in the quilts and consequent fermentation in the combs. He believes in prevention rather than cure, for he knows that the conditions of bee life tend to spread disease with lightning rapidity should it once get a hold in the hive. Its hundreds of inhabitants confined in such a small space, each possessing air organs which penetrate every part of its system, afford every advantage to the spread of microbic diseases.
Should bees ever be seen vigorously fanning at the entrances to a hive without apparent cause, it is a sure sign there is something wrong, and examination should be made at once.
Foul Brood.—This is the very worst scourge to which the bees are subject. It is a disease that attacks the brood in the cells, and, as there are no young bees produced to take the place of those that die, the hive is soon decimated. The disease is easily identified, for the whole of the cells attacked are perforated and of a brown colour, and a most offensive odour is produced.
The disease is probably spread by bees from an infected hive taking refuge in others, or by robber bees entering the infected one. There is nothing to do when virulent foul brood is discovered but to burn the whole contents of the hive.
Dysentery.—This is a disease which principally affects the older bees and is generally caused by feeding too heavily on pollen—more particularly in winter time when proper exercise cannot be taken. The symptoms are a distended abdomen, which is filled with a yellowish brown substance that is discharged copiously. In bad cases it is discharged on the combs.
The best remedy is to add an ounce of table salt to a quart or more of warm syrup and feed the bees outside in a sheltered spot.
Isle of Wight Disease.—This is one of the most mysterious and deadly diseases which affect bees. Further, it attacks the hives in winter when circumstances are all in its favour. Large sums of money have been spent by bee-keepers, and a vast amount of time and thought given by pathologists in the endeavour to trace its cause and remedy, but hitherto without avail.
The usual symptoms are similar to those of dysentery, with a loss of power of flight. In attempting to fly, an affected bee falls to the ground in a helpless condition.
As in dysentery, however, it is the older bees that are affected; the brood and young bees seem immune. It would seem, therefore, that the winter feeding on pollen has something to do with it. Probably because pollen is more of a natural food to them, and because their air organs are not fully developed, the disease does not affect the young bees through that channel.
There are many so-called remedies which claim to be efficacious, but I have no faith in them except in very mild cases. I fail to see how a remedy can be administered when a hive is attacked in mid-winter and the bees are clustered, or when it reaches the stage when paralysis occurs. In such a case there is nothing to be done short of destruction.
If, however, a bee-keeper should have reason to suspect the conditions of a hive, and it is at all possible to feed it outside, I would recommend that the method should be tried, for no harm would be done and possibly a certain amount of good. The food given should be thinner than usual—to counteract the effect of the farinaceous pollen food—and contain double the ordinary amount of salt. The hive should be cleared of any dirt, and the floor-board washed over with a weak solution of carbolic acid.
Should the combs become full of syrup as the result of this feeding, take some of them out and place them near the feeder, replacing them with empty ones.
The outside feeding encourages the bees to take exercise, which is all to their advantage, but it is not permissible where there are large numbers of hives in the district. In such a case a quilt of open material must be placed over the hive instead of the several thick ones, and inside feeding adopted.
Chilled Brood.—Although this cannot in every instance be accounted a disease, yet, unless care be taken, there is no knowing where an incipient case will end. The cause is suggested by the name— the brood in the cells becomes chilled, and the effect is death. As a rule, when this has happened the cappings of the cells become black, and the appearance of an affected comb is something akin to that presented by foul brood. Whenever a hive contains any quantity of chilled brood, the bees should be given to another hive, and the queen, together with the combs, destroyed, unless the hive be a very strong one. In such a case the worst half of the combs can be removed and their space filled with a dummy.
If new combs are added it will generally be found that it is merely to afford facilities to the spreading of the evil. It is useless to add bees to an affected hive, for they will immediately fly away from the danger zone.