WASHINGTON — Scientists yesterday identified a virus as one of the probable causes of the recent wave of honeybee colony collapses across the country.

The study, co-authored by researchers at Penn State University, Columbia University, the U.S. Department of Agriculture, and several other institutions, suggests that the Israeli acute paralysis virus helps trigger the mysterious condition known as colony collapse disorder, which destroyed about 23% of America’s beehives last winter. The paper is being published Friday in the journal Science.

Beekeepers, scientists, and public officials have been searching for the cause of the disorder, which surfaced in 2004 and was formally recognized last year. Unlike other diseases that strike hives, the collapse disorder leaves a colony without most of its worker bees despite the presence of plentiful food, a queen, and other adult bees. It has devastated an industry that produces honey and pollinates lucrative crops such as almonds, oranges, and apples.

The team of scientists who authored the paper emphasized that they have begun to unlock the puzzle but have yet to determine exactly what causes a colony’s abrupt decline.

“This is a major finding,” said Columbia University professor W. Ian Lipkin, an epidemiologist who usually focuses on human diseases. “What we have at present is a marker. We do not think IAPV alone is causing this disease.”

Israeli scientists had previously identified a lethal strain of the virus in their country. Mr. Lipkin said in a telephone interview that American researchers had found a closely related virus that “may be somewhat muted,” or less virulent. Other factors, such as the varroa mite, a well known parasite that attacks bees, may be weakening their immune systems and making them more vulnerable to the virus.

Using the recently mapped honeybee genome, American scientists were able to identify genetic material from viruses and other pathogens in bees collected over the past three years from healthy and sick colonies across the country. They found evidence of the virus in 25 of 30 affected colonies, but just one of 21 unaffected hives.

“The only candidate which was left standing at the end of this very rigorous process was IAPV,” Mr. Lipkin said.

Penn State entomologist Diana Cox-Foster, the paper’s lead author, said she and her colleagues found no evidence that cell phone signals were affecting the bees, as some have speculated. Pesticides on the crops that bees pollinate, which many beekeepers suspect could be harming them, “could be helping to stress the bees, or acting as a potential trigger,” she added.

The researchers said Australian honeybees imported to America in recent years may be the source of the virus. Australia does not have the varroa mite, which may explain why it has not experienced the disorder. Other countries, from Israel to Austria to Canada, have had cases of colony collapse, though not on the same scale as the United States.

It is unclear whether American authorities will bar future imports of Australian honeybees in light of the new research.