Tens of thousands of hardwood trees, mostly maples, have been cut down and destroyed in New York, Ohio, and Massachusetts in an effort to eradicate the invasive Asian longhorned beetle. Forest Service researchers and partners discovered that female Asian longhorned beetles lay down a pheromone trail when they walk across the surface of a tree. The researchers isolated and identified four pheromone chemicals from the trails of virgin and mated females when they are about 20 days old, which corresponds to the time they are mature reproductively. These compounds are attractive to males, helping them initially find a female on a huge tree and relocate her to guard her from other males. The compounds also repel virgin females, probably to help females avoid competition for mates. These compounds have been synthesized and could potentially be useful in managing the invasive beetles in the field using a lure-and-kill method.