Common Bee Diseases and How To Treat Them
[Note: Materials for this page are taken directly from the
Queensland Department of Primary Industries and Fisheries Beekeeping Disease
page. Please refer there for actual beekeeping information.]
European foulbrood (EFB) is a brood disease of honeybees caused by the
bacterium Melissococcus pluton. The disease is endemic throughout
Eastern Australia, but is not known to occur in Western
Australia. Worker, drone and queen bee larvae are all susceptible to
EFB infection. Larvae are most susceptible to infection when they are
less than 48 hours old, and usually die while still in the coiled
state. Poor nutrition and severe stress, for example insecticide
poisoning, often cause this disease to break out.The larvae first turn
yellow then brown in colour. In old larval remains, a secondary
invading bacterium, Bacillus alvei is also commonly present. The
disease is usually noticed in early spring, and to a lesser extent in
When EFB infection is light, treatment is usually not required as the
disease often disappears during a good nectar flow. Requeening of the
hive is also advocated as a treatment. Stress is also an important
factor in the control of EFB. Stress can result from:
European foulbrood can be controlled with the antibiotic
oxytetracycline hydrochloride, (also called oxytetracycline or
oxytet). If measured dosages are fed to bee colonies in the prescribed
manner, the drug will prove an invaluable tool in apiary
- poor nutrition
- working winter honey flows
- excess movements of hives
- insecticide poisoning
- sudden expansion of the brood, resulting in insufficient nurse bees.
Sacbrood is an infectious disease which affects the brood of honey
bees. It mostly occurs as a mild infection which only kills a few
larvae, but it can be more severe. Few hives die out as a direct
result of sacbrood, but many are weakened to an extent where they
succumb to other threats.
Sacbrood is an infection caused by a virus. Remains of larvae that
have recently died are yellow in colour and are highly
infectious. Larval remains more than two months old are brown and dry
and are not infectious.
Requeening infected colonies is a recognised form of control. It is
not practicable to requeen every colony which displays only a few
larvae infected with sacbrood. However, once more than 5% of brood is
infected, thought should be given to replacing the queen with one bred
from a hive showing no sign of the disease. Combs with less than 20%
of the brood infected should be removed from the brood chamber and
placed in the honey super. Replace the combs with foundation if the
bees are strong enough and conditions permit. Hives with mild
infections should be checked every few weeks for any sign of the
Combs with more than 20% of brood infected should be removed from the
hive and could be either melted down or placed in storage for two
months. Combs in storage need to be protected from wax moth. A solar
wax melter is a suitable device for melting down combs on a small
scale. After removing old and known contaminated combs, the hive
should be requeened, packed down and stimulated by feeding sugar syrup
or moved to a honey flow.
Control measures will not ensure immediate removal of the problem from
apiaries but, if brought into general management practice over a
period of time, the sacbrood problem should be reduced. Antibiotic
treatment will not control this disease.
Spores are highly infectious and are carried in contaminated pollen,
by infected foraging bees leaving spores at floral and water sites, by
queens, drifting bees, and drones. Shifting bees on trucks with open
entrance causes drift and hence spread of disease. Spores remain
viable for up to 15 years or more in equipment and soil. Use of
contaminated sites and old equipment could lead to
infections. Interchange of equipment by the beekeepers also spreads
There are three means by which the control of the disease has been attempted:
There is no effective chemical agent that is effective for use against
the chalkbrood fungus therefore chemicals are not recommended for the
treatment of chalkbrood in Australia.
Management practices which reduce the stress on hives also reduces the
number of chalkbrood spores. Maintaining strong healthy colonies has
been demonstrated to reduce the effects of chalkbrood.
Management practices which may reduce the effects of chalkbrood disease are:
- management practices
- use of ‘disease resistant’ bees.
Good hygiene will also help. Change clothes and disinfect smokers,
boots and hive tools using chlorine bleach between apiaries or
- removing ‘mummies’ from bottom boards and around the entrance
- destroying combs containing large numbers of ‘mummies’
- supplying new combs
- providing good ventilation in hives
- adding young adult bees to hives
- not allowing bees to winter in a hive that is over supered
- feeding sugar syrup, fresh uncontaminated pollen or supplements
- maintaining strong hives by regular requeening
- reducing or preventing interchange of hive materials
- not using the same site each year, if possible shift the apiary site slightly.
Some hives are affected with chalkbrood more than others. Most of this
variation in susceptibility is due to differences in the ability of
bees to uncap and remove diseased brood. By selecting queen bees or
obtaining queen bees from hives that show resistance to this disease,
the effects of chalkbrood can be reduced.
A combination of management practices which reduces stress, reduces
chalkbrood spores, maintains strong hives, and selects queen bees that
show resistance to infection, are currently the main ways to minimise
the effects of chalkbrood.
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