Charting Asian Longhorned Beetles' Roaming Habits

By Erin Kendrick-Peabody
June 25, 2003

If the Asian longhorned beetle (ALB) continues its advance, this invasive pest may potentially alter the makeup of North American hardwood forests. Losses to lumber, maple syrup and tourism industries--dependent on healthy hardwood trees--could reach $670 billion.

Now Michael T. Smith, an Agricultural Research Service entomologist at the Beneficial Insects Introduction Research Unit in Newark, Del., has generated new dispersal data that predicts how far the beetle might spread once it begins to invade an area.

This formidable pest was first found in the United States in 1996, a stowaway amidst wooden crates from China. Since then, it's been invading hardwood trees in the East, leaving an indelible mark on New York City and Chicago parks. More than 7,500 trees have succumbed to the pest. Its ravenous larvae feed inside trees, weakening them and disrupting vital nutrient flow.

Determining ALB presence has depended solely upon visual surveys. For this, crews climb host trees--like maple and elm--in search of beetle activity. They scan for small markings where eggs are laid under the bark and for dime-sized holes indicating an adult beetle has exited the tree. Just as it sounds, locating these subtle signs of ALB infestation is time-consuming and costly.

Beetle surveys and the methods used to establish quarantine boundaries have been missing something. That important piece of the ALB puzzle is an increased understanding of the beetle itself--more specifically, how it moves in the environment.

Realizing this, Smith and colleagues conducted the first ALB dispersal research in the beetle's home territory of Gansu Province, China. They marked and released almost 40,000 beetles, collected from nature, and tracked their movements. Their finding? The beetles fly much longer distances than originally thought--even females carrying eggs.

This new dispersal data could be used to establish more reliable survey and quarantine boundaries, increasing the chances of successful eradication.

ARS is the USDA's chief scientific research agency.