Phytosanitation of mountain pine beetle infected lodgepole pine using dielectric fields at radio frequencies

Abstract

As an environmentally friendly alternative to chemical treatment, this research aimed to establish whether dielectric heating at high frequency of infested lodgepole pine (Pinus contorta) boards and logs, obtained from the mountain pine beetle devastated forests of British Columbia, can result in wood free of living fungi, nematodes and insects. The sample set contained 230 boards, 50x150 and 50x100 mm 2 in cross-section and 20 logs, 200-300 mm in diameter; all tested specimens were roughly one meter long. The intention was to test the efficiency of two temperature/time combinations: 56ºC for 30min and 60ºC for 15min that were identified in past works as effective phytosanitary combinations. Data showed that both permutations eradicated all infestation levels and types. The electric field power density per treatment cycle ranged from 23 to 50 kW/m 3 and the total heating cycle varied from 42 to 116 minutes for all pest and wood type combinations tested.

Calentamiento por radiofrecuencia para esterilizar Pinus radiata como material para embalajes. Parte 1: Tiempo total de tratamiento

“…La radiofrecuencia es recomendable para maderas gruesas ya que la penetración es profunda, pero relativamente lenta. Diversos autores han demostrado las condiciones de aplicación de radiofrecuencia (combinaciones de temperatura, espesor o diámetro, tiempo y tipo de ambiente) para que puedan ser eliminados de la madera hongos, insectos y nematodos (Dwinell 1997, Petrič et al 1998, Fang et al 2001, Watanabe et al 2011, Tubajika et al 2007, Lazarescu et al 2015, Lazarescu et al 2009, Uzunovic et al 2013, Dubey et al 2016, Zhao and Wang 2018.…”

Wood sanitization protocol for export packaging of Pinus radiata wood using a radiofrequency heat treatment

“…Alternatively, specific drying cycles are used as sanitization treatments (Ananías and Venegas 2005;Ananías et al 2013). Because of the time it takes to reach the target temperature, dielectric heating at radio frequencies (RF) has been used as an alternative to sanitize wood and eliminate Bursaphelenchus xylophilus and other nematodes (Lăzărescu et al 2011;Uzunovic et al 2013;Lăzărescu et al 2015). For effective sanitization, a minimum temperature of 60 °C must be achieved and maintained for at least for 1 min at the center of the wood, as shown by Hoover et al (2010).…”

Ultrasonic phytosanitation of pinewood nematode infected wood

“…Thus, there is significant need for new non-chemical based alternative treatments. Dielectric heating both a radio and microwave frequency levels was tested with positive results for green logs, timbers and packaging materials thus leading to its adoption as substitute treatment (Lazarescu et al 2010, Hoover et al 2010, Uzunovic et al 2013, Lazarescu et al 2015.…”