Researchers find direct remedy for dragón amarillo

A research team in Florida says it has found a possible treatment for a disease that threatens to wipe out the citrus industry there and even in Costa Rica.

The disease is called greening in English. In Costa Rica, the disease is called dragón amarillo. The Ministerio de Agricultura y Ganadería has declared an agricultural emergency over the problem.

Right now the main way of fighting the disease is to spray against the Asian citrus psyllid, a tiny bug that sucks on leaf sap and leaves behind bacteria.

Costa Rican officials have found some cases in the northern zone, but growers in Florida say the state’s entire $9 billion citrus crop is threatened. The disease also is in California and México.

The University of Florida found three chemicals that stop the spread of the bacteria. The researchers said that the disease starves the tree of nutrients, damages its roots and the tree produces fruits that are green and misshapen, unsuitable for sale as fresh fruit or for juice. Most infected trees die within a few years.

Much of Costa Rica’s orange crop is exported as juice, and it is a major agricultural industry.

Researchers in California are experimenting with a tiny parasitic wasp that lays eggs in insect nymphs, eventually killing them. However, the Florida technique directly attacks the bacteria and not the vector.

The Florida team sprayed greenhouse tree shoots separately with one of three biochemicals and were successful in stopping the bacteria’s spread, particularly with benzbromarone, which halted the bacteria in 80 percent of the infected trees’ shoots, the university reported.

The chemical alters a protein found in the citrus shoots and affects the bacteria’s survival, the university reported.

Experts have predicted that without some remedy, the bacteria, Candidatus Liberibacter asiaticus, could destroy the U.S. citrus industry in 10 years.

The University of Florida said that citrus greening costs $3.63 billion in lost revenues and 6,611 jobs.

Costa Rica has spent more than $1 million in prevention, training and the creation of a lab.

The cost of insecticides against the insect carrier is many hundreds of dollars a hectare, officials have said.

The bacteria also is called huanglongbing, a Chinese name reflecting the fact that the disease was found in that country in the early part of the 20th century. The disease here is called dragón amarillo because the citrus leaves eventually turn yellow and fall off.

The Florida researchers said they expect to begin field experiments with this treatment later this year, according to the university.

Industry experts, though, say it could be five to seven years before a new active-ingredient product could be commercially available because of the amount of time field testing takes and government regulations, the university added.

The disease causes green and misshapen fruit.

The disease causes green and misshapen fruit.

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