Canadian Forest Service Publications
Heat disinfestation of decay fungi found in post-mountain pine beetle wood. 2008. Uzunovic, A.; Khadempour, L.; Leung, K. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, BC. Mountain Pine Beetle Working Paper 2008-14. 12 p.
Available from: Pacific Forestry Centre
Catalog ID: 31158
In early stages of mountain pine beetle attack, blue-stain fungi associated with the beetle are the predominant microorganisms in the trees. As post-beetle standing trees age, a succession of other fungi occurs, including both sap- and heart-rot fungi, which may flourish in red- and grey- attack stages. In this study, 22 isolates from later stages of beetle-attacked wood were assembled, representing eight fungus species, to test the effectiveness of heat treatment to eradicate fungi present in wood, (including 56° C for 30 min (56/30) as adopted by ISPM-15 international standard) and whether slow drying/desiccation increased heat tolerance of selected isolates. Nine isolates survived 56/30, but all were killed by 61° C for 30 min. Results indicated that some fungi may increase their heat tolerance slightly if they have been slowly drying/desiccating prior to treatment. Considering the insulating capacity of wood and that industrial ovens achieve higher temperatures near the wood’s edge and longer core heating times in meeting the ISPM-15 target of 56/30 in the wood’s core, schedules that achieve 56/30 in the core will be sufficient to eradicate most undesirable fungi associated with mountain pine beetle. Also, naturally occurring, aggressive mould fungi will further reduce the chance of surviving fungi to escape from treated wood once it reaches the marketplace. It is hoped that these findings will improve the understanding of perceived versus real threats by fungal organisms associated with beetle-affected wood that may survive 56/30 under lab conditions, and prevent any unsubstantiated restrictive trade practices.