MIAMI -- The much-dreaded citrus canker, which destroys citrus trees and makes their fruit unsaleable, has invaded at least 16 lime groves in the Miami area, according to Florida state agriculture officials.
The disease is caused by the bacteria Xanthomonas axonopodis and has the potential to destroy entire crops. Symptoms are most typically small lesions that can appear on the fruit, leaves and twigs of infected plants. Extreme cases have caused defoliation, severely blemished fruit, reduced fruit quality and premature fruit drop.
Citrus canker was recently found by agricultural officials in a 7-acre lime grove near Florida City, a small agricultural town south of Miami. Trees in approximately 15 suspect nearby groves have been knocked down and burned. This drastic step is the only known way to kill the disease, which is not harmful to humans, but can be spread by them, as well as by wind, rain and equipment used in infested areas. Even the claws of birds can disperse the bacteria as they travel from tree to tree, officials said.
Hardest hit are Miami-Dade and Broward counties in southeastern Florida, where approximately 500 acres of land are under a state-imposed citrus-canker quarantine. Throughout the state nearly 700 acres have been quarantined, which means no trees, fruits or plant parts may be moved from those areas -- however, non-infected fruit from those zones may be exported to non-citrus producing areas, according to agriculture officials. Even here, however, there are stipulations -- the fruit must come from a recently inspected grove and be decontaminated in specially designated packing houses.
While he declined to speculate on the current situation's effect on citrus in the marketplace, Nolan Lemon, public affairs spokesman at the U.S. Department of Agriculture's Animal and Plant Health Inspection Service in Riverdale, Md., said if the spread of the disease cannot be stopped, the results could be drastic.
"It is a very serious problem and can manifest itself everywhere if we cannot eradicate [citrus canker] in Florida," Lemon said. "The continued spread would pose a very serious threat not only to the citrus groves but to the cost at grocery level as well."
A citrus-canker fact sheet posted on the APHIS Web site stated "there are at least three distinct strains or types of citrus canker." It said the current and all previous citrus-canker infestations in the United States have been associated with the "A" strain, which affects members of the Rutaceae plant family, which includes most citrus species and hybrids, especially grapefruit, lime, sweet lime and trifoliate orange.
Citrus canker was first reported in the United States on the Gulf Coast in 1910. It has been declared eradicated here several times, only to consistently -- maddeningly -- resurface. It is believed to have its origins in Southeastern Asia.