Agriculture Reference
In-Depth Information
Even the best colonies are sometimes overwhelmed by mite infestations. Either your
IPM techniques haven't been successful, or a varroa bomb has come home. A bomb
occurs when a nearby colony becomes overwhelmed by a mite population and the con-
ditions are so bad the entire colony absconds, leaving their former home, looking for
a better home. If you are monitoring your mite populations, your sticky board counts
will reflect a sudden influx of mites and warn you of the problem. When mite counts
skyrocket above those safe numbers on the chart you need to act fast to knock down that
mite population before their viruses become endemic; before they infest not only all the
drone brood, but much of the worker brood; and before they damage a significant pro-
portion of the adults in the colony, damaging them to the point of not being able to care
for the next generation of young, and, considering the time of year, perhaps causing the
overwinter death of your colony.
This is why testing for mites is an ongoing management tool, not just a spring and
fall activity. You also have to weigh the consequences of treating a colony of bees that
so far seems to have held its own against mites. Can your colony cope with an event
like this? Can they overcome a large influx of mites? If they can't, then the only choice
is a chemical treatment—and the softest, easiest on the bees, and least toxic choice is
what a safe and sane IPM program calls for. There are only a couple of choices if this is
the case.
First, let me briefly discuss the hard chemicals that are available now. They are pesti-
cides embedded in plastic strips that you place in the colony. Bees walk on them, pick
up a tiny bit of the chemical, which moves all over their body and eventually contacts a
ride-along mite. That mite dies. The amount of chemical used is enough to kill a bug on
a bug. It's a finely-tuned balance.
The chemicals worked well until varroa mites built up resistance and thus the chem-
icals were used more often but accomplished less. Moreover, these chemicals are
quickly absorbed in the beeswax they come in contact with and after only a short expos-
ure time your colony becomes a harbor for poison. Constant exposure to these chemic-
als is very detrimental to queens in that they produce fewer eggs and die younger, and
drones have their reproductive organs damaged when exposed to this stuff. In short, an
inefficient, expensive quick fix ends up being a long-term disaster. Hard chemicals are
not a good answer.
There are a few essential oil products on the market that are effective in knocking
down mites without harming the bees and with only small amounts, if any, being ab-
sorbed into the wax. These are easier on the bees and the wax, and pretty good for con-
trolling mites. If you must use a pesticide in your hives because the mite population
exploded, these are better choices.
