Agriculture Reference
In-Depth Information
ADULT BEE DISEASES
Nosema
Nosema apis is a unicellular parasite of the class of Microsporidia that is now considered
to be a fungus. N. apis has a resistant spore that can withstand temperature extremes
and dehydration. It is a very widespread disease of honey-bees and, when the spores
are eaten by adult bees, they germinate and invade the gut wall. Here they multiply and
produce more spores that are passed out in the waste.
Nosema is common in spring and autumn, and many beekeepers treat the condition
with an antibiotic substance called fumagillin (the tradename of which is Fumadil B),
added to an autumn feed of sugar syrup. Fumadil B ( prepared from Aspergillis fumigatus,
the causative agent of stone brood!) inhibits the spores reproducing in the ventriculus,
but it does not kill them.
Identifying nosema
There are no specific external symptoms of nosema, but the colony's failure to build
up in the spring could be an indication of the disease. Many beekeepers believe that, if
their bees have dysentery, this is a sign of nosema. This is not so. Nosema can be spread
rapidly by dysentery via nosema spores in the faeces the cleaning bees will eat, but
dysentery is not in itself an indicator. Some texts will tell you that bees crawling around
the hive's entrance may also be a sign of nosema. Again, this is not so. It is more likely
to be a symptom of a viral disease or even of pesticide poisoning.
If you believe one of your colonies has nosema, you can do two things to check this.
First, you could obtain the advice of the bee-disease officer in your region, who would
probably ask for a certain number of bees to be sent to the laboratory for analysis,
Second, you could grind up some bees and look at them under a microscope yourself.
You don't need much power to see the very evident rod-shaped spores.
Alternatively, you could carry out a field test on a few of your bees (preferably around
30) from each suspect hive. To carry out this test, follow the procedures outlined
below:
 
 
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