Archive image from page 32 of Diagnosing bee diseases in the. Diagnosing bee diseases in the apiary . diagnosingbeedi392burn Year: 1936 DIAGNOSING BEE DISEASES IN THE APIARY 31 FUNGOUS DISEASES OF ADULT BEES CAUSES It has been known for many years that in Europe a disease of adult honeybees is caused by a common fungus, Aspergillus -flavus. In North America it has recently been found that this same fungus and several others attack adult bees. A. -flavus has already been noted as attacking brood (p. 23). When recently emerged bees are kept at a temperature about 12° or 14° below that of the br
Archive image from page 32 of Diagnosing bee diseases in the. Diagnosing bee diseases in the apiary . diagnosingbeedi392burn Year: 1936 DIAGNOSING BEE DISEASES IN THE APIARY 31 FUNGOUS DISEASES OF ADULT BEES CAUSES It has been known for many years that in Europe a disease of adult honeybees is caused by a common fungus, Aspergillus -flavus. In North America it has recently been found that this same fungus and several others attack adult bees. A. -flavus has already been noted as attacking brood (p. 23). When recently emerged bees are kept at a temperature about 12° or 14° below that of the brood nest they may be attacked and killed by Mucor Memalis, a fungus closely related to the common black bread mold. Old bees are not affected by this fungus. Spores of pathogenic fungi get into the digestive tract of bees with food or with water. If a bee comes in contact with fungus spores, some of them to the mouth parts and be swal- lowed later. Nonpathogenic fungi are unable to grow within the stomach of bees, and the fungi themselves may be killed. Patho- genic fungi, on the other hand, grow readily. At first the fungus grows within the stomach, but later the muscles and other soft tis- sues are penetrated by numerous fungus branches, and death re- sults. When dead bees are kept under moist conditions, the fungus may grow through the body wall and form spores on the outer surface (fig. 20). Figure 20.—Adult workers and a drone bee killed by Aspergillus flavus. Spores of the fungus are seen on tbe bodies of tbe bees. IMPORTANCE Losses of adult bees caused by fungi are usually of little economic importance. When pathogenic fungi grow within the hive on combs, frames, dead bees, etc., late in the winter or early in spring, fungous diseases are most likely to cause significant losses. This can be
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