Diseases of bees / Ministry of Agriculture and Fisheries.

Date:
1948
Catalogue details

Licence: Public Domain Mark

Credit: Diseases of bees / Ministry of Agriculture and Fisheries. Source: Wellcome Collection.

    22/36 (page 14)
    Signs of Infection with Acarine Disease. Crawlers may appear after a period of confinement to the hive caused by unfavourable weather. These crawlers leave the hive fluttering their wings and often one or more wings are carried at an abnormal angle to the body, as if dislocated (the so- called ‘‘ K-winged individuals ’’); frequently, the abdomen is distended. Falling from the edge of the alighting-board on to the ground these infected bees crawl away from the hive in all directions until, becoming chilled or exhausted, they climb to the tips of grass-stems or other herbage, or huddle together in small groups. When the percentage of infected bees within the colony is high, as frequently happens in the autumn and spring, mass crawling may occur, and thousands of bees in the condition described above ~ may be found for many yards around the hive. Bee-keepers should keep a careful watch on their colonies not merely for crawlers, which only appear in the later stages of the disease, but also for other signs of debility, such as listlessness and inactivity among the older bees on fine days when bees from other colonies are flying hard. It cannot be emphasized too strongly, however, that reliance on outward signs as evidence of the presence or absence of acarine disease is never to be recommended. The only reliable method of diagnosis is a microscopical examination by a competent person of the thoracic tracheae of each individual of a representative sample of 25-30 bees taken at random from the colony concerned. As many bee-keepers have neither the facilities nor the time to make such examinations and since it is impossible to arrange for regular annual or biannual examination of a sample of bees from every colony in this country, bee-keepers will be well advised to apply the methyl salicylate treatment described below to each of their colonies of bees every year as a pre- cautionary measure against infection with acarine disease. Such treatment will do harm neither to the bees nor to their brood, nor will it cause robbing or taint the honey. Treatment of Acarine Disease. There are three important methods of treating colonies of bees suffering from this disease: (1) the Manipulative method; (2) the Frow (or Modified Frow) treatment; (3) the Methyl Salicylate treatment. In addition it should be remembered that diseased colonies can easily be lost through lack of stores and feeding may be an essential part of the treatment, particularly in the spring. There is also danger of robbing if the colony is weak and the hive entrances of infected colonies should be reduced as necessary to guard against this. Perforated zinc, which allows of thorough ventilation, is ideal for this purpose. Very often the queen of an infected colony is herself infected, particularly if she was reared in that colony and, since a healthy fertile queen will play a large part in overcoming the disease, requeening is strongly advised when possible. Since the mite gains access to the bee’s tracheal system during ; the first few days of adult life, the queen should be raised and mated in a | healthy colony and introduced into the infected colony only when she is laying, i; by which time she will ibe well past the critical age for infection and may i be expected to be immune to this disease. (1) MANIPULATIVE METHOD. As already stated, a bee can only become infected with Acarine disease during the first four or five days of adult life, after which it is immune from this disease. Also, the mite responsible for this