Ash bats are one of baseball's most iconic pieces of equipment. Players have been using them for more than a century now because they're durable and don't shatter as easily as maple or birch bats.

However, an exotic beetle, the emerald ash borer, is threatening baseball's supply of ash bats, writes Brian Mann of NPR. The beetles, which were accidentally imported from Asia, have destroyed millions of ash trees throughout the United States. Soon the ash supply won't be able to meet the demand.

Here's more from Mann, who spoke to Rawlings plant manager Ron Vander Groef:

"If the ash borer is not controlled, it'll wipe out the entire species of white ash," Vander Groef says. "We will not be able to make any more pro bats or retail bats or anything out of white ash because it will be gone."

The Rawlings plant makes about 300,000 bats a year and about 70 percent of those have been made of ash. Vander Groef says the company's supply could be gone -- or become unaffordable -- within three years.

Of course, there's a much larger issue here than baseball bats. After all, maple and birch make for fine bats too. The damage the beetles are doing to the ecosystem is a far greater concern.

"It's bordering on catastrophic," says Deborah McCullough, a scientist at Michigan State University. She was one of the first entomologists to realize that emerald ash borers had invaded.

Federal and state officials across the country are working to try to quarantine areas affected by emerald ash borers. That means no untreated wood can be moved out of those areas. They're also experimenting with insecticides and with the release of a variety of wasp that targets ash borer larvae.

In some areas 90 percent of ash trees have been destroyed by the beetle. The hope is they will be able to eliminate the emerald ash borer infestation and save the country's ash trees.

An exotic beetle is threatening baseball's supply of ash bats. USATSI

Many of baseball's all-time great highlights -- the shot heard 'round the world, Babe Ruth's called homer, Hank Aaron's 715th home run -- feature ash bats. Many players still use them today, but the emerald ash borers are putting the ash supply at risk.

As fans, that may not seem like a huge deal. After all, baseball will still be played, albeit with more maple and birch bats. For the players though, it could represent a big change. They're awfully superstitious about their bats.