ACOUSTICS DETECTION OF PESTS IN STRUCTURES, TREES, AND SOILS
2008 Annual Report
1a.Objectives (from AD-416)
The objective of this cooperative research project is to develop an acoustical monitoring tool for detecting subterranean termites. Primary target pest is the Formosan subterranean termite (Coptotermes formosanus) in structures, trees, and soil.
1b.Approach (from AD-416)
Acoustical apparatuses will be constructed to detect unseen infestations of insects. Devices will be based on recognition of sound-producing acitivities. Recognition will be developed from databases sounds recorded under an array of substrates and environmental conditions.
The major objective of this project is to develop an acoustical monitoring tool for detecting FST. During the 2007-2008 reporting year, the accelerometers (device that measures acceleration forces) have proven to be the most sensitive detectors for termite detection, but are expensive and require attachment to test materials. Laser Doppler Vibrometers (LDV)(an instrument that measures vibrations) are another means to detect termite vibrations that do not require physical contact with the test substrate, and can measure vibration at distances of many meters. We compared a commercial (LDV) with a sensitive accelerometer for comparison. The accelerometer noise floor was significantly less than a state of the art (LDV) at 1-2 milliwatts power and remained relatively constant over frequency of 1-10 KHz, while the laser’s noise floor increased linearly with vibration. Side by side comparison tests with the accelerometer and laser used on Formosan Subterranean Termite (FST) infested simulated sheetrock walls and in an infested building in New Orleans resulted in similar detection of single soldier Head-Banging (HB) with 100 times amplification of both. Improved design of LDV could improve the sensitivity and result in a useful detector. We have investigated inexpensive sensors such as microelectrical-mechanical sensors (MEMS) microphones and accelerometers and modified phonograph cartridges as termite detection transducers. Amplified phonograph cartridges can detect single soldier (HB). We are investigating the use of wireless MEMs accelerometers for remote detection. Soldier HB is the largest amplitude termite vibration and eliciting such behavior reliably could increase detection probability. Playing back several field recorded HB wave files has failed to elicit HB behavior. An acoustic based in-ground monitor to detect termite activity was developed and is currently being tested. Insect acoustics software was developed that allows efficient acoustic data collection and analysis, metadata updating, easy searching of wave files and all associated metadata including pictures. We are continuing research on termite tremulation (shaking) and HB. Progress in this project is monitored through Annual FST Technical Committee Meetings, reports, regular meetings with cooperators, routine phone calls, and e-mail correspondences.