Queen bees bred to withstand varroa mite
5:00AM Wednesday July 04, 2007
A bee colony is being established on an offshore island to breed queen bees tolerant to the bee-killing varroa mite for New Zealand's honey producers.
Establishing the colony off the North Island follows three years of artificial breeding and selecting queen bees for tolerance to the pest, the National Beekeepers Association conference in Dunedin was told yesterday.
HortResearch scientist Mark Goodwin said that when the project started, the most varroa-tolerant queen was "18 per cent" - 18 of 100 of her breeding cells opened in a hive did not have varroa. After the breeding and selection programme, that had improved to 86 per cent.
Dr Goodwin said highly resistant queens were exposed to varroa and three months later scientists could not find any mites, suggesting the parasite had not reproduced.
An industry management group had found the 2000ha Great Mercury Island, 8km off Coromandel, to be free of feral bees and next spring the breeding programme would shift there. The bees would continue to be exposed to the mite.
"Any extra selection needed, varroa will do it for us. Any colony not varroa-tolerant will be killed."
Commercial beekeepers will have access to varroa-tolerant queens, which Dr Goodwin said would reduce chemical treatment costs.
Many North Island beekeepers have treated their hives twice a year, at $40 to $50 a hive for each treatment, since varroa arrived in April 2000.
Using varroa-tolerant queens could reduce that to once every year or two years.
Dr Goodwin said varroa had wiped out the feral bee population and 20,000 managed colonies in the North Island, forcing beekeepers to import 10,000 to 20,000 colonies from the South Island.