A serious pest of hardwood trees in its native China that by 1998 had been found in 14 states in the United States, where it has no known natural enemies. APHIS is now working to detect and destroy the beetle, which is virtually impossible to eradicate with pesticides because it bores deep inside trees to lay its eggs; the only known suppression method is to remove and destroy infected trees. The agency reports that the beetle, which already has led to the destruction of many trees in parts of New York, could destroy millions of acres of hardwoods—including maples, horse chestnuts, poplars, willows, and elms—if it becomes established in the environment. APHIS believes that the beetle has been entering the United States in solid wood packing materials such as pallets and crates from China. For that reason, in late 1998, it banned all shipments from China containing such packing materials if they have not been treated to kill the pest.