German researchers say that lithium chloride “is highly effective” in killing Varroa mites, a parasite commonly listed as one of the major reasons for high mortality among the pollinating insects. “Experiments … clearly demonstrate the potential of lithium as a miticidal agent with good tolerability in worker bees providing a promising basis for the development of an effective and easy-to-apply control method for mite treatment,” they say in the journal Scientific Reports.
Annual treatments are needed to control Varroa mites, but there are only a small number of chemicals available and no new agents have been registered in a quarter-century, say the researchers, based primarily at the University of Hoffenheim. “Despite increased attention for Varroa treatment, periodic high colony losses have been reported in nearly all countries in Europe and North America,” says the study. The scientists say tiny amounts of lithium chloride killed 90 to 100 percent of the mites without significantly affecting mortality rates for the bees.
Francis Ratnieks, an apiculture professor at the University of Sussex, expressed some skepticism that lithium chloride would be a practical solution, according to Real Clear Science. “I think it will be difficult in practice to apply lithium salts to colonies to kill Varroa and get the same level of control” as treatment with oxalic acid, he said. “There also are the wider issues of regulation and potential contamination of the honey with a product that would not ordinarily be there.” Nonetheless, the German researchers are “speaking with companies to get a lithium chloride treatment refined, approved, and in the hands of beekeepers,” said Real Clear Science.