'Greening' disease threatens the core of U.S. citrus crops

— -- A botanical disease that has hit Florida and now threatens California is raising fears that the price of citrus fruits and juices will soar in coming years.

Government agencies and the produce industry are working to stop the spread of "citrus greening." Discovered in China in the 1800s, the disease has a global history of devastating crops. "Areas that have had greening no longer have a commercial citrus industry," says Robert Norberg, an economist with the Florida Department of Citrus.

It's already "a 10" on a threat scale of 1 to 10 in Florida, says Andrew Meadows of Florida Citrus Mutual, a growers' organization. "It is the biggest issue the industry is facing right now. It is killing trees as we speak."

California has declared all-out war on the tiny Asian citrus psyllid, which can carry the bacteria and was first spotted there over Labor Day weekend.

The psyllid has long been a resident of Florida. It first appeared there in 1998, says Denise Feiber of the Florida Department of Agriculture. Signs of citrus greening — fruit that stays green and bitter and leaves that turn yellow — appeared in Florida groves in 2005.

The disease has spread to all of Florida's citrus-growing counties. Neither insecticides nor removal of infected trees has been able to stop it. A tree can be infected for years before yellowing leaves make it apparent, so the infection can spread to the rest of the grove long before the grower knows there's a problem.

The threat got worse when psyllids were found in California. Florida grows 71% of U.S. citrus; California grows 27%. Most of Florida's crop is for juice. Most of California's is fresh fruit. The total market was worth $2.7 billion in 2005-2006, according to the Department of Agriculture.

The threat is most severe in Florida and California, but it isn't limited to those states. The disease has been detected in Louisiana. The psyllid has been seen in Texas, Georgia, Mississippi, South Carolina, Guam and Puerto Rico.