Honeybee parasite threatens crops
Almond growers in California feel sting of tiny mite
By Juliana Barbassa
Originally published February 4, 2005
A tiny pest is decimating honeybee colonies across the country, worrying beekeepers and farmers who depend on the insects to pollinate their crops.
Honeybees pollinate about a third of the human diet and dozens of agricultural crops, including almonds in California, which produces 80 percent of the world's supply.
"It's simple. We can't produce almonds without bees," said Scott Hunter, an almond farmer near Merced who's getting ready to lay 2,500 hives among the bare branches of his trees.
A $1 billion-a-year crop, the nuts have become the state's top agricultural export, ahead of wine and cotton.
The bees pollinate California's almond orchards from mid-February to early March, then move to apple orchards, cherry groves and melon patches. They pollinate New England's cranberry bogs in early summer.
That's why researchers, beekeepers and growers are scrambling for ways to save the honeybees. Because almonds are the first crop to flower, the state's growers are the first to suffer from the bee shortage.
Experts believe the mites may have arrived in the mid-1980s from Asia, where they coexisted with local honeybees.
In their years in North America, the eight-legged pests have devastated wild bee colonies and radically altered beekeeping. The pinhead-sized mite - the Varroa destructor - feeds on honeybees and their larvae. In some areas, they've destroyed as many as 60 percent of the hives.
The mites also have developed a resistance to pesticides - a trait they've been able to spread to their progeny faster than scientists have been able to develop new compounds to fight them off.
"The fact that we don't have any compounds commercially available really is a serious issue," said Gloria DeGrandi-Hoffman, research leader at the Carl Hayden Bee Research Center in Tucson, Ariz. "This is a very serious problem."
Researchers such as DeGrandi-Hoffman are looking for options, working on isolating bees with a natural resistance to mites and experimenting with elements such as plant oils and the mite-fighting compounds produced by some bees.
But the process takes time, and the mites adapt quickly, the researcher said.
"You challenge them with a particular compound and, given time, they will become resistant to that," she said.
Meanwhile, in California's 550,000 acres of almond orchards, the bee shortage is leading growers to offer beekeepers almost twice what they paid last year for their bees' services - up to $100 per hive. Growers have been riding a wave of good prices and strong demand, but they say the mite crisis is squeezing their profits.
Dan Cummings grows 4,000 acres of nuts in Butte, Colusa and Glenn counties. He's one step ahead of other farmers, since he's also part owner of 9,000 hives - many of which pollinate his crops.
Still, he said he's seen honeybee rentals go from being about 8 percent of his total expenses to nearly twice that.
The higher prices soften the blow to beekeepers, many of whom have seen their colonies cut in half by mites. But they still worry that without a quick solution, their livelihood - and their lifestyle - may be in danger.