Regulatory Treatments for Solid Wood Packing Materials

Research Issue

Current regulations require that solid wood packing material (SWPM) be heat treated or fumigated prior to export were put in place partly to prevent further introductions of ALB.  Alternative treatments are needed that are more cost-effective, energy-efficient and that eliminate the environmental concerns associated with chemicals used in fumigation.

Our Research

Low pressure, achieved by applying a vacuum to a system, imposes a controlled atmosphere and desiccating environment that results in death of wood-infesting insects.  Larval ALB either exposed directly to vacuum or inserted into wood at various moisture levels, were subjected to different temperatures and pressures to determine desiccation rates and lethal percentage weight loss. 

Expected Outcomes

Potential SWPM treatment to be evaluated for operational use.

Research Results

Some ALB larvae died at 26 % weight loss and all were dead at 40% weight loss.  Desiccation under low pressure vacuum also killed ALB pupae and eggs.  The desiccation rate of ALB larvae under vacuum was constant until death, but decreased as larvae approached complete desiccation (approximately 60 % weight loss).  ALB larvae lost weight at a rate of 3.35 % weight loss per hour at 20 mmHg and 20 ºC.  Lethal vacuum time at 40% weight loss was estimated to be 13.2 hr, for exposed ALB larvae treated at 20 mmHg and 20 °C.  Under the same vacuum conditions, lethal time was estimated to be approximately 51.4 hr for ALB inserted into wood blocks with 16.6 to 21.6 % moisture content.  Temperature, pressure, and relative humidity affected desiccation rate.  Larvae desiccated slower with decreasing temperature, increasing pressure, and increasing internal wood moisture. 

Chen, Zhangjing; White, Marshall S.; Keena, Melody A.; Poland, Therese M.; Clark, Erin L. 2008. Evaluation of vacuum technology to kill larvae of the Asian longhorned beetle, Anoplophora glabripennis (Coleoptera: Cerambycidae), and the emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae), in wood. Forest Products Journal. 58(11): 87-93.

Research Participants

Principal Investigators

• Zhangjing Chen, Virginia Polytechnic Institute & State University
• Marshall S. White, Virginia Polytechnic Institute & State University
• Melody Keena, USDA-Forest Service- NRS Research Entomologist