Beekeepers can kill varroa mites by using a chemical miticide, Apistan, within affected colonies. But some don't want to use chemicals, either for environmental or economic reasons, Caron reports. And, mites inevitably develop resistance to chemicals, prompting beekeepers to boost the dosage. Too much miticide can kill the bees as well as the mites, since both are arthropods. Young bees are particularly vulnerable to the miticide. Clearly, Caron says, "it's no good if your patient dies on the operating table."
In search of a longer-term solution, Camazine uses high-powered microscopes and other laboratory instruments to learn exactly how mites and their viruses affect bees. Strategies for addressing these problems may include breeding hardier bees and improved mite treatments, he says. At the USDA, for instance, scientists are investigating a long-lasting gel containing formic acid-a natural component of honey. Formic acid, legalized for mite treatment in Canada, does kill mites, but it evaporates quickly and, therefore, must be reapplied frequently. A formic acid gel may provide beekeepers with an important new alternative to Apistan, as it slows the rate of release of the chemical. Meanwhile, Camazine says his group is studying essential oils, such as eucalyptus, as possible natural mite repellents in the northeastern region.
"We need research to solve the mystery of exactly why these mite-infested bees
are dying," Camazine says. "Do the mites directly damage worker bees? Do they
spread viral infection or weaken the bees' immune system, allowing other
diseases to kill the colony? Do mite-infected bees have lower cold tolerance?
This knowledge could help
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Contact: Ginger Pinholster
gingpin@udel.edu
302-831-6408
University of Delaware
1-Jul-1998