Scientists looking into the dramatic decline of the honeybee population in the United States say they are baffled by the developments.  But they told the U.S. Congress Thursday the drop is threatening the production of a significant portion of the U.S. food supply that relies on honeybee pollination.   VOA's David McAlary reports.

The drop in the U.S. honeybee population began last October. U.S. Agriculture Department official Caird Rexroad says beekeepers across the continent began reporting unexplained losses of 30 to 90 percent of their colonies.

"If you notice when you walk through the clover in the yard barefoot, you'll no longer be stung by a honeybee," he said.  "It's very unfortunate."

Getting stung is no pleasure, but to hear Rexroad tell it, it is a far lesser evil than the loss of the honeybees. He told the House of Representatives Agriculture Committee the collapse threatens a $15 billion segment of the U.S. farm economy that relies on pollination. Especially hard hit are growers of almonds and other nuts, berries, fruits, and vegetables.

"These outbreaks of unexplained colony collapse pose a threat to the pollination industry, the production of commercial honey, and the production of at least 30 percent of our nation's crops," he added.  "Furthermore, with pests and diseases of bees increasing over the last few decades, we have reached critical point for the bee industries."

Rexroad and other scientists cannot explain the precipitous bee decline. Their main suspect is the verroa mite, a bug that invaded the United States in the 1980s. U.S. Agriculture Department research has found the mites kill bees by feeding on them, transmit viruses, and have become resistant to many insecticides.

But other possibilities include pesticides or other environmental toxins, migratory or hive stress that weakens bees' immune systems, and various viruses and bacteria.

Pennsylvania State University bee expert Diana Cox-Foster is part of a study group uniting several national and state scientists who are analyzing bees, wax, honey and pollen from more than 100 colonies across the country to seek clues to the insects' demise. She says that whatever the cause, the country needs a new breed of honeybees to overcome the present challenges.

"The working group recognizes the importance of trying to breed honeybees that are more resistant to diseases and the impacts of parasites," she said.  "Developing new genetic strains of bees may be essential to the future of beekeeping."

The United States is not alone in honeybee loss. Cox-Foster and others told Congress that Canada and parts of Europe are also experiencing unexplained honeybee death, but they do not know if it is part of the same phenomenon.

"I know it is a growing problem," she added.  "This is a global issue and being recognized as a problem."

Beekeeper David Ellington from the north central U.S. state of Minnesota says the crisis shows how little is known about honeybee biology and his industry. He complained to the lawmakers that the business gets much less research support from government and academia than regular agriculture, and many of his colleagues are about to give up.

"If there is a glimmer of hope that we could, in some manner, improve the lot of beekeepers, the atmosphere of this industry would be greatly improved and we would see new, younger beekeepers moving in," he said.