NOTES FOR BEEKEEPERS

New Zealand Journal of Agriculture, Volume 71, Issue 3, 15 September 1945, Page 309

NOTES FOR BEEKEEPERS

Inspection of Hives for Foul-brood

WITH the coming of spring and warmer days, each hive in the apiary should now be showing signs of increased activity. If the colonies were closed down in the autumn with a generous quantity of honey for winter stores, the hives, especially those with young and vigorous queens, will now contain at least three or four frames of brood. Care will have to be exercised at this time and for the next two months to ensure that the stores required to feed the ever-increasing quantity of young bees and brood do not become short, as it is at this period that colonies are in the greatest danger of starvation. It must be realised that the bees rapidly deplete existing stores when brood rearing is being accelerated, and, because they may display great activity on fine days with the gathering of pollen, beekeepers should not assume that sufficient nectar is also being gathered. Such activity, on the other hand, is a warning that the colonies may require supplementary feeding to sustain their early brood rearing until greater quantities of nectar are available. Colonies need all the young bees they can rear at this time of the year. Weather conditions are likely to be erratic, and provision should be made to ensure the maintenance of brood rearing by transferring combs of honey from clean hives with a sur-

plus to those where the stores have been consumed more rapidly. This method is preferable to artificial feeding, but it is of the utmost importance that this practice is carried out only when the beekeeper is certain that the apiary is free from foul-brood. Where there are no spare combs of honey available for this purpose the colonies should be artificially fed with a syrup made up with equal parts of sugar and water. Great care should be exercised when performing the early spring work in the apiary, and every precaution should be taken to avoid any unnecessary robbing. Should any stray bees appear and settle on exposed combs while a hive is being inspected, the hive should be closed down immediately and apiary work suspended, as such bees will subsequently become too numerous and then develop wholesale robbing, but when the bees are busy gathering nectar or pollen a more prolonged examination will be fairly safe and progress can be made. The replacement of all damaged or ill-fitting supers, lids, and bottomboards is essential, as hives in this condition in the spring encourage stray bees to rob, and also provide the robbers with easy access to the honey stores. Where robbing has commenced the colonies that are being plundered will

have little or. no chance of survival unless all the hive openings are sealed with grass or some other suitable material until the trouble subsides.

One of the main objects of examinations at this time of the year is to inspect each brood comb carefully to ascertain if American foul-brood (Bacillus larvae) is present, as this disease attacks only the brood or larvae bees. The presence of this disease is usually detected by the appearance of the cell cappings. When the brood is healthy .the larvae are pearly white and the cappings uniform in colour with an even convex form, but cells containing diseased larvae are generally darker in colour and more concave or shrunken than the surrounding healthy ones. This circumstance alone is not sufficient evidence to decide that the colony has foul-brood, and it is necessary to investigate further. If, on opening any such suspicious cell, a coffee-coloured and shrunken larvae is found, which, on inserting a straw or wooden match, adheres to the point and can be drawn out rope-like for a distance, as illustrated, undoubtedly American foulbrood is present. Infected larvae usually die about the time they enter the chrysalis stage, or when the cells are capped over, although where infection is severe in a colony some infected larvae will be observed that have died as they were about to change into the

form of adult bees during the early pupae period. . Where cells display dark perforated cappings, and a gluepot smell is noticeable, the infection is in an advanced form. Following the last phases of decomposition, the remaining dead matter dries into a black scale on the bottom of each cell. Causes of Infection The principal causes of infection are:—■ 1. Healthy colonies robbing diseased colonies. 2. Supplying colonies with honey or combs from infected hives. 3. Leaving exposed to bees any combs or honey from a diseased hive. 4. Manipulating healthy colonies after diseased ones, without first thoroughly washing the hands and sterilising the hive-tool. 5. Hiving swarms from unknown sources. Initial foul-brood infection is generally introduced to a hive following the robbing of honey from a

nearby colony previously weakened by this disease. The spores of Bacillus larvae are, in such instances, contained in this robbed honey, where they may remain inactive within the hive for a very long time. These quickly become active and produce the disease immediately the infected honey is fed by the nurse bees to bee larvae. - When this disease first develops in a colony there are just a small number of cells infected, but because there are thousands of spores in the minute particles of infected matter and the disease is extremely contagious, such cells rapidly become more numerous and seriously reduce the number of hatching bees necessary to maintain colony population. Ultimately, the colony is in a weakened condition and is then easily robbed by other bees in the vicinity. Control Measures To prevent the contamination of other colonies in the apiary or vicinity control measures must be applied immediately the infection is noticed. While strong colonies can be successfully treated, for disease at certain

times with proper management, the destruction by fire of any infected bees, frames, and hive equipment is recommended.

When a diseased hive is to be destroyed by fire the work is best done

in the evening, as every precaution must be taken to prevent any bees drifting to other hives, or exposing.

any infected honey where healthy bees can reach it. A couple of teaspoons of calcium cyanide on a piece of cardboard inserted into the entrance will kill. the bees. To make a quick and effective burn a fire with plenty of flame should then be made in a hole that has been dug as near the infected hive as possible. The hive and all infected material should be placed directly upon the fire (bot-tom-board and roof are removed to create a draught through the supers) and, when all is consumed, the hole should be filled in to bury the remaining ashes. Should American foul-brood appear in the apiary, or should there be any suspicion of the presence of the disease, the Apiary Instructor for the district should be notified, and immediate steps must be taken to prevent any possible spread to other hives. By notifying the local Apiary Instructor all information concerning the proper measures to adopt for the eradication of the disease may be obtained.

—E. SMELLIE,

Apiary

Instructor, Christchurch.

PASSION FRUIT

Bulletin No. 135, “Passion Fruit Culture,” is now available free from the Department of Agriculture, Wellington.