If the red imported fire ant becomes established in California, the insect's indiscriminate appetite and testy attitude could cost Californians from $387 to $989 million a year, according to a UC Davis researcher.

"There's no way of predicting how far and how fast the ants will spread in California," said Karen Jetter, a postdoctoral researcher at the UC Davis-based Agricultural Issues Center. Jetter and colleagues released their findings on the potential economic impact of the fire ant in the January issue of California Agriculture magazine, published by the University of California's Division of Agriculture and Natural Resources.

The fire ant, already established in several Southern states, was discovered in San Joaquin Valley almond orchards in 1997 and has since shown up in many parts of Orange, Riverside and Los Angeles counties. Last October, it also was found and destroyed on the Cal Expo grounds in Sacramento County.

The authors estimate that, in the absence of eradication efforts, it would take 10 years for the ant to become established and could inflict costs totaling from $3.9 to $9.9 billion during that period, mostly to households.

A $65.4 million, five-year eradication program is being coordinated by the California Department of Food and Agriculture and the nursery industry to prevent, lessen or delay the projected losses from the ant's arrival in California.

Based on the biology of the fire ants, the researchers think it is unlikely that they will be eradicated during the first five-year funding period. The project will be reviewed, however, and considered for extension based on progress made during the first five years.

In agriculture, the ant's large mounded nests can damage mowing and harvesting equipment, irrigation lines, and electrical equipment. The ants girdle and kill young citrus trees and attack cattle and other livestock. They also damage vegetable and melon crops by eating developing fruit, seeds, roots and tubers and subject nursery and hay crops to quarantine regulations.