US - The honeybee population has experienced less severe die-offs over winter than in 2014, but there are still significant threats, according to a specialist from Purdue University.
Professor of Entomology Greg Hunt said that after the cold, wet winter of 2013-14 in much of the US, observers reported one of the largest bee die-offs ever recorded, with a mortality rate of about 65 per cent for Indiana.
Based on his primary investigation and discussions with beekeepers, Mr Hunt estimated this year's losses at about 29 per cent.
"It seems much better than the year before, even though it was another cold winter."
According to the US Department of Agriculture, honeybee pollination is worth about $15 billion a year in crop production.
But the honeybee population has been declining for years, with the US losing about one-third of its hives annually. Experts estimate the number of honeybee colonies in the US dropped from about 4 million in the 1970s to about 2.5 million now.
The reasons for the bees' decline aren't entirely clear, although there are likely a number of contributing factors, Mr Hunt said.
Especially baffling is a phenomenon known as colony collapse disorder, when adult worker bees disappear from their hives for no apparent reason, leaving the immature bees in the colony to starve.
"Although colony collapse disorder has generated a lot of attention, symptoms haven't been seen in Indiana or in other states in the past two years," said Mr Hunt.
Another threat identified by Mr Hunt is the use of neonictoinoid insecticides. In a 2012 study, Mr Hunt and other researchers found high levels of concentrated neonicotinoids in dead bees around agricultural fields.
It is believed the neonicotinoids spread to surrounding plants and soil by release from the planting machinery.
Another significant danger facing the bee population is a parasite known as a Varroa mite. The mites feed on bee larva and transmit viruses.
If left unchecked, a mite infestation can destroy an entire colony.
Beekeepers who notice too many mites in their hive should use a commercially available pesticide designed specifically to control Varroa mites, advised Mr Hunt.
"The earlier an infestation is identified, the better chance you have of saving the colony," he said.
Replacing a hive that has been lost or damaged by Varroa mites or other causes can be expensive and time-consuming.
"Normally, the bees are ready to pollinate in mid-May.
"If a beekeeper has to replace a colony, pollination could be delayed until mid-June."
TheCropSite News Desk
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