Originally aired August 30, 2002 techlive
Listening for Larvae
Acoustic tech could help eradicate a pest that has already destroyed thousands of trees and could
threaten more.
By Lynne Topkis, Tech Live
Since it was first detected in Brooklyn, New York, in 1996, the Asian longhorned beetle (ALB) has led to the
destruction of more than 7,000 trees in New York and Chicago. And since there is no pesticide or known predator to
the ALB, it has the potential to do tremendous damage to US forests. As "Tech Live" reports tonight, to prevent the
ALB from becoming a national problem the Department of Agriculture's Animal and Plant Health Inspection Service
(APHIS) has this week launched a pilot program to eradicate the pest in New York City using acoustic detection
technology.
Because "you are looking for just a small oviposition site, an egg laying site, or an exit hole," the current eradication
technique -- visual survey -- makes it difficult to determine if a tree is infested before it's heavily damaged, explained
Therese Poland, research entomologist at the Department of Agriculture's Forest Service.
Equipment for the job
The acoustic detection system, on the other hand, picks up any feeding sounds inside the tree not audible to the
human ear.
Developed by the Oak Ridge National Laboratory, the system uses a sensor attached to the tree called an
accelerometer. The accelerometer delivers a signal to a charge amplifier, which amplifies it on a display.
If there's acoustic vibration signals of larvae feeding coming from the tree, the amplitude will increase. The signal from
the charge amplifier also goes into a handheld computer.
The computer then analyzes the signal to see if the sounds from the tree are from ALBs. Each time the larvae make a
characteristic feeding sound, the "beetle bite counter" goes up. The bites can also be heard on a traditional headset. All
this equipment is worn on a belt around the waist and weighs only about 3 pounds.
Aiming at the right target
Cyrus Smith, senior researcher at Oak Ridge National
Laboratory, helped to develop the acoustic detection
technology. TechTV asked him how the device knows that the
sounds are from an Asian longhorned beetle. "Just like your
voice is different from my voice," he explained, "each of the insects has a different sound. The algorithm that we
developed is specifically looking for the bite of an ALB, which has a different sound signature from any other beetle."
The equipment can be set to detect any one of five beetle sounds. But just like other detection techniques (such as
facial recognition), this technology can also produce false positives. It depends on what level of sensitivity the system
is set for.
"When the instrument detects a beetle bite, it saves it to a file where it can be sent to a person that can do further
analysis to determine if it is in fact a true beetle bite," Smith said. This should catch false positives.
In the case of a confirmed infestation, the tree is destroyed.
But will it work in the long run?
The acoustic detection technology is being tested in the state of New York. But Joseph Gittleman, who's the program
director of the ALB cooperative eradication program in the state, says he has his doubts about its effectiveness.
In addition to the time involved to set up the system, he says he is concerned with the other life stages of the beetle.
"As we all know, eggs don't make chewing sounds," he said, "and until the eggs hatch and the larvae get to a
sufficient size where they are chewing on the tree, detection through [acoustic] technology will be impossible."
Originally aired August 30, 2002
Modified September 4, 2002
Copyright 2003 TechTV Inc. All rights reserved.
