It is routine for Alden Marshall to lose bees during the cold winter months, but this year was something different.
“I usually lose around 20 to 30 percent of my bees,” the Hudson resident said. “But this year it was close to 50 or 60 percent.”
Marshall, a beekeeper who maintains hives at farms throughout Southern New Hampshire, is just one of many to experience a loss of bees.
"It's a huge concern for the future," said Michael Smolak of Smolak Farms in North Andover. "They pollinate our plants. This isn't an easy business and we rely on them to help grow our crops."
But the cause of their deaths remains a mystery.
Alan Eaton, an entomologist with the University of New Hampshire Cooperative Extension, said the cause could be anything from the stress the bees are under to produce to pathogens in the air causing viruses.
“Various studies point to different factors of things causing problems with the way we handle domestic honeybee colonies," Eaton said.
In May, the Environmental Protection Agency released a report looking at Colony Collapse Disorder, which they say is the reason 10 million beehives have been lost in the last five years. The report concluded that varroa, a parasitic mite, is the most detrimental pest to the colonies.
But Marshall said the disorder hasn’t really affected his bees or those of other beekeepers he has spoken to throughout the state.
“I don’t think it is (Colony Collapse Disorder),” he said. “The true symptoms include absconding of live bees leaving behind young unemerged bees. That isn’t what’s happening here.”
Instead, Marshall said, it is primarily because of nosema, a fungus which affects bees’ digestion of pollen.
But, he said, it’s hard to tell if that’s the main cause.
“There is just so many viruses that aren’t even diagnosed,” Marshall said. “There could be diseases we don’t even know about.”