Concerns over varroa mite resistance
ABC News in Science: The spread of a pesticide-resistant mite, which can decimate honeybee hives, is causing concern among beekeepers in New Zealand.
Dr Mark Goodwin of the New Zealand Institute for Plant & Food Research says while Varroa destructor has been in New Zealand for ten years, they’ve only recently found evidence of resistance to the synthetic pyrethroid treatments used to control them.
http://www.abc.net.au/science/articles/2010/03/24/2853860.htm