> Uraguayan researchers also found that spraying an extract of propolis
> decreased the number of AFB spores in colonies.
Good subject for study IMO. I should think that results of spore counts are
dependant on the measurement method, though.
I wonder if they are reporting spore count -- live and dead -- or just
viable spores, and how they determined viability if that is the case, since
I should think that culturing spores would give different results than a
microscopic examination.
It has long been my contention that although AFB spores have been observed
to remain viable for long times and be very resistant to heat, that time and
environmental influences -- like heat, atmosphere, chemical reactions, solar
and other radiation, coating with wax and propolis -- reduce their vitality
over time.
Given that, in order to infect larvae sufficiently to cause what we call
AFB, a number (more than one) of spores must be in the right place at the
right time, and be able to germinate in the short time before the window of
opportunity closes. Too slow, and the opportunity is gone AFAIK. (I don't
know how a half-infected larva would turn out).
In other words, even if AFB spores are weakened by any of those factors --
time, heat, atmosphere, chemical reactions, solar and other radiation,
coating with wax and propolis -- and although they may still be demonstrated
to be viable in lab tests, the spores may not be sufficiently viable to
actually infect larvae effectively in a real world hive situation, or may
require greater numbers to achieve infection, especially in less susceptibe
strains of bees.
> However, as Allen says, beekeepers have long found that a supply of used
> drawn combs are one's most valuable asset. Bees clearly prefer to store
> honey in dark comb above the brood.
I have always been amazed how southern beekeepers are able to replace dead
colonies and destroyed comb over a fairly short period without apparent
economic damage when the same losses would destroy a northern beekeeper. Up
north, we have problems replacing typical normal 30% annual shrinkage in
numbers without sacrificing crop.
It is quite typical for a northern beekeeper to buy 10% of the operation's
total numbers annually in package bees to compensate for losses over the
year. Although splitting can replace the annual attrition, splitting
sufficiently to replace the losses would burden the operation excessively.
On the other hand, southern beekeepers, of course, sell those packages and
then go on to pollinate and make a crop. The bees they sell are often
surplus, and would be in the trees unless shaken and sold.
Of course, too, southern farmers plant two or three crops a year on the same
acreage that a northern farmer would plant and harvest only once.
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