Fumagilin-B

Fumagilin-B is an antibiotic used in the treatment of Nosema infection. It works by attacking the actively multiplying disease-producing parasites in the bee’s digestive tract. It is primarily used in treating package bees and overwintering colonies.>

Fumagilin-B should be fed only in sugar syrup. Dusting and extender patties are not effective. Fumagilin-B is very stable in sugar solution.

Nosema apis

Nosema apis, the most common strain of nosema is caused by the protozoa spore Nosema apis that infects the epithelial cells of the honeybee ventricles. Nosema apis is very well controlled by Fumagilin-B.

In the fall, after all honey supers have been removed, apply medicated syrup (1:1 or 2:1) at a rate of 190mg fumagillin activity per colony.

For example, dissolve 454g of Fumagilin-B in 100 US gallons of sugar syrup and feed each colony 2 US gallons (treats 50 colonies), or dissolve 454g of Fumagilin-B in 50 US gallons of sugar syrup and feed each colony 1 US gallon (treats 50 colonies).

In the spring, feed medicated syrup (1:1 or 2:1) at a rate of 95mg fumagillin activity per colony.

For example, dissolve 454g of Fumagilin-B in 100 US gallons of sugar syrup and feed each colony 1 US gallon (treats 100 colonies), or dissolve 454g of Fumagilin-B in 50 US gallons of sugar syrup and feed each colony ½ US gallon (treats 100 colonies).

Nosema ceranae

The best treatment method for Nosema ceranae, or for Nosema apis in conjunction with Nosema ceranae, has not yet been established.

Preliminary indications are that the spring treatment may have to be modified due to increased persistence of Nosema ceranae. At this time, based on information available, Medivet suggests to use the following treatment method until research in progress has been completed:

For fall treatment, use the same method as for Nosema apis (see above).

In the spring, feed medicated syrup (1:1 or 2:1) at a rate of 30mg fumagillin activity per colony, 4 times at 1-week intervals.

For example, dissolve 454g Fumagilin-B in 40 US gallons of sugar syrup and feed each colony 1 pint (treats 320 colonies). Repeat 3 more times at 1-week intervals.

Schedule to complete treatment at least 4 weeks before anticipated supering.

Feeding Medicated Syrup

Package Bees — All packages should be treated as the bees are stressed from moving, the population is small and replacement is slow. The first three weeks are the most critical.

Overwintering Colonies — Unable to fly in winter, honeybees defecate within the hive, so infected bees contaminate the comb and frames with the Nosema spores. Other bees clean up and thereby infect themselves and others. Control of severe infections of Nosema disease in overwintering colonies may take a minimum of two years of feeding medicated syrup in the fall to repress spring outbreaks.

For best results

When incorporating Fumagilin-B into sugar syrup, make certain to use good agitation to assure uniform distribution of the Fumagilin-B, otherwise some colonies will get higher dosages while others will not get enough. Do not prepare medicated syrup more than 24 hours in advance of feeding.

Do not incorporate Fumagilin-B into hot sugar syrup. Heat will damage fumagillin.

Do not barrel-feed medicated syrup. Heavily infected colonies are not good foragers and may get very little medication.

Do not feed medicated syrup later than 4 weeks before adding supers for surplus honey.

References:

• Fumidil B product literature, Medivet Pharmaceuticals, High River, Alberta, Canada
• Honey Bee Pests, Predators, and Diseases, 3rd Edition ©1997, edited by Roger A. Morse and Kim Flottum