ALBANY, N.Y. — Wildlife biologists studying a mysterious fungus killing off hundreds of thousands of bats around America want to find out if they can repopulate caves decimated by the disease.

Researchers will introduce 79 healthy little brown bats to two hibernation sites in Vermont hit hard by the fungus, which may have killed as many as 500,000 bats in the eastern United States over several winters.

Scientists suspect a fungus that thrives in cold, moist caves causes white-nose syndrome, named for the sugary smudges of fungus on the noses and wings of hibernating bats.

The repopulation experiment starting Tuesday at caves in Bridgewater and Stockbridge, Vt., is not aimed at curing the disease. But it could show whether affected caves can sustain new populations of hibernating bats.

"Can you have bats successfully survive there? Or will they develop the disease even if there aren't any infected bats there?" asked Al Hicks, a wildlife biologist for New York's Department of Environmental Conservation.

Hicks said that if the bats shipped in from Wisconsin survive the winter, that could provide evidence that bats can be successfully reintroduced to caves that housed infected animals. It also could show whether the disease persists at hibernation sites even after infected bats are gone.

Entrances at the two sites are screened to keep in the bats. Gates will keep out people.

First noted in upstate New York in 2006, the disease has spread around the Northeast and has been detected as far south as Virginia. Researchers worry about a mass die-off of bats, which help control the populations of insects that can damage wheat, apples and dozens of other crops.

The repopulation project is a cooperative effort among conservation officials from Vermont, New York and the federal government.