Gordon and Krugner. 2020. Mating Disruption by Vibrational Signals: Applications for Management of the Glassy-Winged Sharpshooter.  Book Chapter

Gordon and Krugner. 2020. Mating Disruption by Vibrational Signals: Applications for Management of the Glassy-Winged Sharpshooter. Book Chapter

The glassy-winged sharpshooter (GWSS), Homalodisca vitripennis, is a generalist insect and a major pest of grapevines. GWSS is a vector of the bacterium Xylella fastidiosa, causal agent of Pierce’s disease that can lead to grapevine death within few years after infection. This chapter discusses the problem and current GWSS control methods. Then, the focus changes to efforts in developing a novel control method that uses synthetic vibrational signals to disrupt mating and, thus, population growth. A step-by-step method for creating effective playback signals is described and discussed. The method was termed “D.I.E.,” which stands for Describe, Identify, and Execute. The first step is to describe the basic biology of the insect pest with emphasis on communication behaviors. From there, one can begin identifying which candidate signals disrupt communication. Finally, execution tests are conducted to determine which signals effectively disrupt mating in laboratory, and more importantly, in the field. While there are still steps needed for large-scale implementation in the field, the basic biological questions related to whether synthetic vibrational signals can disrupt mating are answered affirmatively. The next direction will be to develop a mechanism of signal transmission across large areas. In addition, season long field trials are needed, taking into consideration natural insect movements into and out of treated areas. Gordon S.D., Krugner R. 2020. Mating Disruption by Vibrational Signals: Applications for Management of the Glassy-Winged Sharpshooter. In: Hill P., Lakes-Harlan R., Mazzoni V., Narins P., Virant-Doberlet M., Wessel A. (eds) Biotremology: Studying Vibrational Behavior. Animal Signals and Communication, vol 6. Springer, Cham. P....
Gordon et al (2019) Transmission of the frequency components of the vibrational signal of the glassy‑winged sharpshooter, Homalodisca vitripennis,within and between grapevines

Gordon et al (2019) Transmission of the frequency components of the vibrational signal of the glassy‑winged sharpshooter, Homalodisca vitripennis,within and between grapevines

The agricultural pest, Homalodisca vitripennis, relies on vibrational communication through plants for species identification, location, and courtship. Their vibrational signal exhibits a dominant frequency between 80 and 120 Hz, with higher frequency, lower intensity harmonics occurring approximately every 100 Hz. However, previous research revealed that not all harmonics are recorded in every signal. Therefore, how the female H. vitripennis vibrational signal changes as it travels through the plant was investigated. Results confirmed that transmission was a bending wave, with decreased signal intensity for increasing distance from the source; moreover, at distances of 50 cm, higher frequencies traveled faster than lower frequencies, suggesting that dispersion of H. vitripennis signal components may enable signaling partners to encode distance. Finally, H. vitripennis generates no detectable airborne signal (pressure wave), yet their low vibrational frequency components are detectable in neighboring plants as a result of leaf-to-air-to-leaf propagation. For instance, with isolated key female signal frequencies, 100 Hz was detected at a 10 cm gap between leaves, whereas 600 Hz was detectable only with a 0.1 cm gap. Together, these results highlight the complexity of vibration propagation in plants and suggest the possibility of the animals using the harmonic content to determine distance to the signaling H. vitripennis source.   Gordon, S.D., Tiller, B., Windmill, J.F.C. et al. J Comp Physiol A (2019)....
Krugner R, Gordon SD.  2018.  Mating disruption of Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae) by playback of vibrational signals in vineyard trellis.  Journal of Pest Management Science.

Krugner R, Gordon SD. 2018. Mating disruption of Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae) by playback of vibrational signals in vineyard trellis. Journal of Pest Management Science.

BACKGROUND Glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae) is an important vector of the bacterium Xylella fastidiosa, the causal agent of Pierce’s disease of grapevine. Area-wide insecticide applications have suppressed GWSS populations for ca. 25 years, but reduced levels of insecticide susceptibility have been reported. Therefore, alternative methods of control are needed. Objectives of this study were to evaluate efficacy of playback of vibrational mating communication signals for disrupting mating of GWSS in a natural vineyard setting and evaluate spectral properties of signal transmission through vineyard trellis. RESULTS Playback reduced mating of GWSS on grapevines. A total of 28 (out of 134) male-female pairs mated in the control treatment (silence) and only one (out of 134) pair mated when treated with the vibrational signal playback. Playback of vibrational signals through vineyard trellis was affected by distance from signal source, with frequency composition and intensity being the highest at the signal source and lowest on vines positioned away from the source. Frequency composition in canes housing test insects decreased exponentially as distance from the source increased, whereas the relative amplitude of analyzed frequencies decreased linearly. CONCLUSION Although further studies are needed prior to method implementation, data from this study continue to support integration of vibrational mating disruption with current methods to suppress GWSS populations.   Krugner and Gordon.  2018.  Mating disruption of Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae) by playback of vibrational signals in vineyard trellis.   Pest Management Science....
Mazzoni V, Gordon SD, Nieri R, Krugner R.  2017.  Design of a candidate vibrational signal for mating disruption against the glassy-winged sharpshooter, Homalodisca vitripennis, Pest Management Science. 73:2328-2333.

Mazzoni V, Gordon SD, Nieri R, Krugner R. 2017. Design of a candidate vibrational signal for mating disruption against the glassy-winged sharpshooter, Homalodisca vitripennis, Pest Management Science. 73:2328-2333.

The glassy-winged sharpshooter (GWSS), Homalodisca vitripennis, is an important pest of grapevines due to its ability to transmit Xylella fastidiosa, the causal agent of Pierce’s disease. GWSS mating communication is based on vibrational signals; therefore, vibrational mating disruption could be an alternative to insecticides for suppression of GWSS population. Our objectives were to identify spectral features of female signal that elicit male signaling, design disruptive signals able to alter male perception and acceptance of a female, and determine the signal intensity required for future field applications. Results showed that male responses to playback of modified female signals were significantly reduced by 60-75%when part of the female signal spectral components above or below 400 Hz were deleted. Playback bioassays showed that transmission of an 80 Hz pure frequency tone to plants completely suppressed male signaling to female signal playback, even if the disruptive signal amplitude was 10 dB lower than the female signal playback.  Although the mechanism underlying cessation of male signaling activity in the presence of disruption is not yet understood, results suggest that an 80 Hz vibrational signal should be tested in laboratory and field experiments to assess its efficacy in disrupting mating of GWSS Mazzoni V, Gordon SD, Nieri R, Krugner R. 2017. Design of a candidate vibrational signal for mating disruption against the glassy-winged sharpshooter, Homalodisca vitripennis, Pest Management Science....
Gordon SD, Sandoval N, Mazzoni V, Krugner R.  2017.  Mating interference of glassy-winged sharpshooters, Homalodisca vitripennis.  Entomologia Experimentalis et Applicata. 164:27-34

Gordon SD, Sandoval N, Mazzoni V, Krugner R. 2017. Mating interference of glassy-winged sharpshooters, Homalodisca vitripennis. Entomologia Experimentalis et Applicata. 164:27-34

Animal communication is a complex behavior that is influenced by abiotic and biotic factors of the environment.  Glassy-winged sharpshooters (GWSS), Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), primarily use vibrational signaling for courtship communication.  Because GWSS is a major pest, transmitting the plant pathogenic bacterium Xylella fastidiosa, interruption of communication is a possible avenue for control.  Playback of white noise, pre-recorded female signals, and artificial female noise (continuously overlapping female signals) significantly reduced mating of GWSS when compared to silent control mating trials.  Furthermore, to begin to determine the mechanism underlying playback control, female signaling activity was recorded in the presence of stimuli.  In response to playback of female signals, females signaled (duet-like) more often than females tested in the absence of playback.  After the first playback, almost two-thirds of females signaled a response within 3s.  Additionally, one-third of the females signaled within 1s after cessation of white noise, and significantly more in the time periods following noise termination.  Results highlight how GWSS responds to differing competitive disturbances in the environment and lays important ground work that possibly could be used to develop pesticide-free control methods.   Gordon SD, Sandoval N, Mazzoni V, Krugner R. 2017. Mating interference of glassy-winged sharpshooters, Homalodisca vitripennis. Entomologia Experimentalis et Applicata....