As a boy, Jack Armstrong watched his grandfather turn a love of fishing into America's first commercial cricket farm, growing and selling the insects as live bait.

Six decades later, the family owns two of the largest cricket farms in the country, in Georgia and Louisiana, shipping up to 17 million of the jumping critters each week to zoos, theme parks, and reptile owners.

At first glance, everything is chirping. But a virus has virtually wiped out the cricket-growing industry in Europe, and it's hopped the Atlantic, industry leaders say. Already, house crickets – the only species allowed for commercial sale in the United States – are in short supply, leaving buyers struggling to find enough.

"We've faced challenges over the years, but nothing like this," says Mr. Armstrong, manager of Armstrong's Cricket Farm in West Monroe, La. "This is the biggest crisis the industry has ever faced, and if we don't get a handle on it, many more growers are going to fall."

In June, Lucky Lure Cricket Farm, among the oldest and largest suppliers in Florida, was forced to close its doors. Owner Beth Payne believes that densovirus, as the malady is known, arrived in a shipment of infected worms from a farm in California.

Ms. Payne says she spent thousands of dollars cleaning and sterilizing the farm in an attempt to keep her business afloat. But when millions of crickets continued to die soon after hatching, leaving her unable to fulfill orders, and when debts approached $500,000, she had no alternative to declaring bankruptcy, she says.

The Leesburg farm, established in the 1950s as a small-time bait supplier, had grown so large that by this year it was a major provider of crickets as reptile food to theme parks, including Disney's Animal Kingdom, SeaWorld, and Busch Gardens.

Meanwhile, in Michigan, the Top Hat Cricket Farm laid off 30 employees this summer for what owner Dave Eldred hopes will be a temporary shutdown. "We have already cleaned our facility top to bottom and sanitized every surface in several ways," he says.

The virus is harmless to humans, industry experts say, and affects only one species, the common house cricket (which isn't the kind chirping outside bedroom windows). Still, it is crucial to prevent the virus from gaining a foothold here.

"Even after 10 years, it remains impossible to commercially raise house crickets in Europe," says Jon Coote, chairman of the British Herpetological Society, who has studied the disease on both sides of the Atlantic.

"In Europe, we raise at least another three separate cricket species commercially for reptile food," he says. "The US cricket industry ... [needs] to convince the US authorities to allow them to commercially raise an alternative species."

Earlier this year, Mr. Coote got together with many leading growers in the US, including the Armstrong family, to plot strategy.

"They agreed to not import any more live insects from Europe and also to donate funds to research this virus," Coote says. Unfortunately, he says, the group – including himself – forgot to put Canadian cricket growers on the banned list. "It is from Canada that I suspect the virus has spread to the US," Coote says.

Armstrong, having watched the devastation in Europe, says he feels fortunate that his family's operation has so far not been affected. He says his managers acted to stave off the virus even before reports of its arrival in the US.

"The first thing we did was go into full lockdown," he says. "That means we're not taking mail in from other farms.... The main thing is you have to get clean."

However, Armstrong's Cricket Farm cannot keep up with the demand, Armstrong says.

After Lucky Lure went under, one buyer forced to look elsewhere was the Central Florida Zoo in Sanford. It had a standing order of up to 13,000 insects a week to provide protein for its salamanders, geckos, frogs, toads, and tarantulas.

"We have a big collection, so we have a lot of need. But it's kind of like a mad dash to get crickets," says Jennifer Stabile, the zoo's keeper of amphibians.

"We get whatever we can from other suppliers, and when no crickets are available, we have to go to other forms of feeding," she says. "We don't know when it will end. It's a waiting game."