ALBANY (AP) -- An invasive, destructive beetle first detected in the southwestern corner of the state has spread to the Catskill forest preserve hundreds of miles to the east.

The state Department of Environmental Conservation said Wednesday that an infestation of emerald ash borer has been found in a 15-square-mile area of northern Ulster County in the Catskills. Larvae of the metallic green beetle burrow into ash trees, eventually killing them.

The DEC has banned transport of untreated firewood to stop the spread of the ash borer and other destructive insects. The agency plans roadside checks for this weekend's NASCAR racing event at Watkins Glen to make sure firewood brought by campers is purchased locally or heat-treated.

The beetles have also been found in Greene, Steuben, Livingston and Cattaraugus counties.

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