Acoustical Detection of Early InstarRhynchophorus ferrugineus(Coleoptera: Curculionidae) in Canary Island Date Palm,Phoenix canariensis(Arecales: Arecaceae)

Abstract

The red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier), recently found in Curaçao and Aruba, has become an economically significant palm tree pest in many tropical and subtropical regions. By the time a palm infested with RPW displays visible damage, larvae have destroyed much of the trunk internal structure, typically resulting in tree mortality. Acoustic technology may enable pest managers to detect and treat early RPW infestations before tree mortality, and to reduce unwanted importation and/or exportation of infested palms. Experiments were conducted in Aruba to determine the detectability of sounds produced by early instars in open, urban environments and in enclosures with ca. 10 dB acoustical shielding. To distinguish RPW signals from background noise, recordings first were analyzed to identify larval sound impulse bursts, trains of 7-199 impulses, 3-30-ms in duration, where impulses within the train were separated by less than 0.25 s. For a burst to be considered a larval sound, it was specified that a majority of its impulses must have spectra that match mean spectra (profiles) of known larval sound impulses more closely than profiles of background noise or known nontargeted sound sources. Based on these analyses, RPW larval bursts were detected in > 80% of palm fronds inoculated with neonates the previous day. There were no significant differences between burst rates in enclosed and open environments, but the shielding provided by the enclosure enabled detection of early instars from greater distances. Thus, there is potential to use acoustic technology to detect early RPW infestation in either minimally shielded or open environments. In addition, because late-instar impulses ranged to higher amplitude and had greater diversity of spectral features than with early instars, it may be possible to identify late-instar infestations based on the amplitudes and the diversity of sound features detected.

Effects of Hypoxia on Acoustic Activity of Two Stored-Product Pests, Adult Emergence, and Grain Quality

“…The acoustic devices were set up as described in Herrick and Mankin (2012). A sensor-preamplifier module (model SP-1L Acoustic Emission Consulting [AEC], Sacramento, CA) was attached at the end of the waveguide (probe) passing through the drilled acrylic covers of the aquarium tanks into the infested grain in the jars.…”

Effects of Hermetic Storage on Adult Sitophilus oryzae L. (Coleoptera: Curculionidae) Acoustic Activity Patterns and Mortality

“…The setup for monitoring and recording insect signals was similar to that described in Herrick and Mankin (2012). A sensor-preamplifier module (model SP-1L Acoustic Emission Consulting [AEC], Sacramento, CA) was attached at the end of the waveguide (probe) passing through the sealing cork into the infested grain in the jars.…”

Characterization of Sounds in Maize Produced by Internally Feeding Insects: Investigations to Develop Inexpensive Devices for Detection ofProstephanus truncatus(Coleoptera: Bostrichidae) andSitophilus zeamais(Coleoptera: Curculionidae) in Small-Scale Storage Facilities in Sub-Saharan Africa

“…Generalpurpose sound analysis software (Raven Pro Version 1.5; Charif et al 2008) was used to screen and preprocess the recordings. Spectral and temporal pattern analyses of the larval impulses were conducted using DAVIS, a custom-written insect sound analysis program (Herrick & Mankin 2012;Dosunmu et al 2014). It should be noted that the AED-2010, whose frequency bandwidth extends to 2 MHz, filters out signals below 1 kHz to reduce the level of background noise.…”