(Dec. 9) SAN DIEGO — A quarantine has been put into effect in San Diego County by the U.S. Department of Agriculture.

The quarantine — which covers a 117-square-mile area of northern San Diego County — follows the discovery of adult Mexican fruit flies in two places in the county shortly before Thanksgiving. Though no boundaries have been established, Animal Plant and Health Inspection Service officials are working on compliance agreements with growers, taking surveys and beginning to remove fruit.

Forty-eight adult fruit flies and two larvae were found in as many as 17 orchards in a 2.5-mile diameter of Valley Center, just north of San Diego. That area is home to production of citrus, avocados, persimmons and a small amount of exotics.

Joel Nelsen, president of California Citrus Mutual, Exeter, said grapefruit and valencia oranges are the primary citrus commodities in that area.


Larry Hawkins, spokesman for the USDA, said that although the flies have only been found on citrus so far both citrus and avocados will be affected by the quarantine.

Hawkins said he expects the quarantine to last as least until the spring, though he added that it is difficult to put an date on it. The quarantine will last through three life cycles of the flies, and those cycles vary depending on the temperature.

“We can’t be too precise about how long it will last,” he said. “It’s going to depend on what the weather is like this winter. The cooler the temperatures, the longer the life cycle and the longer the quarantine.”


In the meantime, an eradication program, including the removal of the host fruit where the flies have been found, has started. Chemicals also will be used to kill the flies, and Hawkins said sterile fruit flies might be introduced to help eradicate the population.

Hawkins said growers also would initiate a commodity treatment program to ensure that any commodities coming from that area are free of pests. Hawkins said no contaminated product made it out of the area.

“As soon as we detected the insects, we put hold notices on the properties and stopped all shipments of fruit from that area through the packing houses,” he said.

Nelsen said the situation was well in hand.

“Fortunately, most of the people down there are responsible members of the industry and they know they can’t be in a position to exacerbate the problem,” he said.