Lance Yamashiro's exotic crops of wasabi and Japanese radishes used to attract the attention only of chefs and grocers. Lately his produce has caught the eye of a new breed of food enthusiasts -- thieves.

Farmers in Hawaii are finding their wares endangered not only by what nature dishes out, but also by criminals capitalizing on weaknesses in rural security and making off with everything from bananas to bees, pesticides to plows.

"Mother Nature's been hitting us hard," said Yamashiro, who has lost crops and equipment on his 100-acre farm to theft. "If the human factor sets in and hits us harder, I'm going to have to lay off employees."

It is not just Hawaii; stolen farm and construction equipment amounts to an estimated loss of $1 billion annually nationwide. Add to that tens of millions of dollars in thefts of produce from farms, and farmers say they have an epidemic on their hands.

"To them, it's 'What's a banana?' or 'What's a papaya?' " said Yamashiro, who said he has been hit by thieves an average of twice a month. "But when the market is really short and we're getting premium dollar, it hurts."

Hawaii's agricultural capital is here on the Big Island, which is also the state's center of farm theft. Varied crops, from the well-known Kona coffee and macadamia nuts to the more exotic lychee, mangosteen and rambutan, cover nearly a million acres. Theft there amounts to about $1 million in losses each year, Alan Takemoto of the Hawaii Farm Bureau Federation estimates.

Thieves have pulled off heists on farms throughout Hawaii and nationwide. Orange trees -- 2,000 of them on one night -- were uprooted in Tulare County, Calif. Thefts of chemical fertilizer have been attributed to methamphetamine labs.

"Anything that can be converted to cash is a target," said Vern Inouye, the owner of Floral Resources/Hawaii, whose Pahoa farm was robbed of as many as 2,000 anthuriums in a recent heist.

"Thieves are creative, so we have to stay creative," said Diane Ley, a deputy on the state Board of Agriculture. "It keeps shifting, just like the weather."

Many farmers say they have increased security, using dogs and high-tech equipment. Yamashiro added about $5,000 in security cameras and other equipment -- but it, too, was stolen.

"Their property is so huge, it's very hard to maintain any kind of control over it," said Lt. Steven Guillermo of the Big Island police.

Even on small farms, it can be tough to keep thieves out. Prowlers used to target Bob Peters's one-acre macadamia nut farm in Naalehu when he went out for the day.

"The whole field would get cleared," he said.

Aside from the hurdles of securing a large piece of property, farm theft is tough to prove and even tougher to prosecute.

"There's no proof of title that goes along with a basketful of apples," said Robert Thompson, a lawyer in Kansas City, Mo., who specializes in agricultural law and has a grain and cattle farm.

Ley said the state Department of Agriculture plans to begin a pilot program this summer, pairing members of her staff with police, prosecutors and farmers. Participants will educate vendors on stolen food and visit stores and farmers markets and may request receipts to prove the purchase of produce.

It is a step in the right direction, said Ulf Wiel-Berggren, who is frustrated that vendors at the Hilo Farmers Market keep buying from those who show up with duffels or garbage bags full of cheap produce.

"When somebody comes here with stolen fruit, you see it or you feel it," said Wiel-Berggren, who has lost everything from avocados to hand tools.

He said it is disheartening to see the fruits -- literally -- of one's labor disappear. "You look at these avocados," he said. "Almost ready, almost ready -- and then they're gone."

Lance Yamashiro installed alarms and cameras and also uses his dogs to help guard his farm from thieves.