Ultrasonic phytosanitation of pinewood nematode infected wood

Amir Sohi,Adnan Uzunovi,Stavros Avramidis

doi:10.4067/s0718-221x2016005000010

Amir Sohi, Adnan Uzunovi + Show 1 more

Open Access

https://doi.org/10.4067/s0718-221x2016005000010

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Abstract

Pinewood nematode (Bursaphelenchus xylophilus) mortality was investigated after ultrasonic treatment at 20 and 40 kHz frequency. Experiments were conducted with infected small wood specimens that were ultrasonically treated for 1, 3, 5 and 7 hours and two variable temperature conditions, namely, a gradually increasing from ambient to a maximum of 70oC and a decreasing from ambient to a minimum of 5oC. The results revealed that the ultrasonic treatment itself had no significant effect on the nematode mortality at the 5oC level, while at the 70oC level, considerable nematode mortality was observed in short time periods and at 7 hours of sonic exposure it reached 100%. Therefore, certain combinations of timing and frequency of ultrasonic waves and produced heat can be effective in killing pinewood nematodes thus resulting in phytosanitized wood.

Highlights

Many non-native organisms are transported and dispersed through the human-mediated trade of goods
As per the Montreal Protocol on Substances that Deplete the Ozone Layer, it is only allowed under the Quarantine and Preshipment (QPS) exemption to eliminate quarantine pests, and the Critical Use Exemption designed for agricultural users with no technically or economically feasible alternatives (Anonymous 2009b)
In our study two ultrasonic instrument setups were used with different frequencies and power levels, the results of the tests were nearly the same. This means that there was no specific difference between the effects of the ultrasonic energy on eradicating pinewood nematodes at 20kHz/200watts and 40kHz/320watts combinations

Summary

INTRODUCTION

Many non-native organisms are transported and dispersed through the human-mediated trade of goods. At sufficiently high acoustic power inputs, microbubbles form at various nucleation sites in the fluid These bubbles grow during the rarefaction phase of the sound wave and in the compression phase, the bubbles are compressed to a minimum radius where they collapse releasing a violent shock wave which propagates through the medium. Taylor et al (2011) investigated the potential for high intensity ultrasound for the phytosanitation of wood products for decay, mold and termites They concluded that the ultrasonic treatment was not effective in killing these organisms in wood and did not appear to have the potential to be a stand-alone wood pasteurization treatment. The pinewood nematode (Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle) was selected as a choice test pest since it is perceived a major forest pest requiring reliable phytosanitary treatments

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSIONS