PRINCETON -- Employees of the U. S. Department of Agriculture's Animal and Plant Health Inspection Service came to the Ace Hardware Retail Support Center Friday, searching for a potentially harmful beetle. They found one, but they're still not sure if it's the right one. The APHIS employees were part of the department's Safeguarding, Intervention and Trade Compliance program in Elk Grove Village. The compliance program's mission is to identify the entry and distribution of agricultural products, which may harbor harmful exotic plant and animal pests, diseases, or invasive species that could seriously damage America's crops, livestock, and environment. Dor/ Mobley, public affairs specialist for APHIS, said Monday her department is issuing a recall on artificial Christmas trees with wooden trunks because of a problem with Japanese Cedar Longhorn Beetles. Mobley said the SITC employees were in Princeton as part of trace back and trace forward inspections being conducted in an attempt to determine the source of an infestation discovered in Michigan. Mobley said the inspections began after a Michigan consumer purchased one of the Christmas trees and discovered the beetle. The consumer notified the Michigan Department of Agriculture, which sent the beetle to APHIS for identification. "After we id'd it, we found it was a questionable pest, one of quarantine significance," Mobley said. After determining a shipment of the trees was at the Ace warehouse, the employees were dispatched to Princeton. Mobley said they found one live beetle in Princeton, but as of press time, it was not yet identified. "We're not sure whether it is the same beetle we are taking this action in regard to, or if it's a different beetle," she said. "When we know, it will determine what our further actions will be in Illinois. We're in a holding pattern." Calls to Ace in Princeton on Monday were directed to Paula Erickson, spokeswoman for Ace's corporate headquarters in Oak Brook. "We're working with the USDA, but there's not yet any cause of action," Erickson said. Erickson said the USDA had been dealing with Ace's merchandising department, and the company was aware of Friday's inspection. Erickson said Ace Hardware put a freeze on the item in question last week, so none would be shipped out of Princeton. However, the Christmas trees are not exclusive to Ace and are carried by other retailers. Mobley said regulations are in place to prevent the importation of the insects. The trees must be made of treated wood and the shipment must include an import permit. Sometimes regulations aren't enough. "The shipment had the proper paperwork," Mobley said. "Apparently, the treatment was not effective."