Global Challenges and Innovative Management of Bark and Wood Borers in Planted Forests

Report by Hervé Jactel, INRAE, and Christoph Orazio, IEFC, Coordinator of the IUFRO Task Force Resilient planted forests serving society & bioeconomy

The IUFRO conference: "Global challenges and innovative management of bark and wood borers in planted and natural forests" took place on 29-31 August 2023 in Bordeaux, France, and was kindly hosted by IEFC and INRAE and supported by ONF, LUTHYL project (Ecophyto, France Bois Forêt). 

Global changes, including climate change and economic globalization, pose serious threats to the health of the world's forests by favoring the emergence or invasion of an increasing number of forest pests. Wood and bark beetles play a prominent role in this context due to the spatial extension and intensity of their damage, with long or chronic outbreaks, causing the mortality of a considerable number of trees or forest areas.

Many methodologies can be applied to the monitoring and control of these insects, which justified the gathering of knowledge and skills of many IUFRO Working Parties and Task Forces. This joint conference aimed to provide knowledge and tools for action for forest scientists and practitioners searching for solutions to mitigate the risk of wood and bark beetle attacks.

Key topics

• Monitoring and management of the large pine weevil
• Population dynamics of the spruce bark beetle
• Molecular and physiological studies of wood boring insects
• Drought and heat related host tree – bark beetle interactions
• Invasions of bark beetles and wood borers
• Precision pest management of bark and wood borers
• Novel monitoring and modelling tools for the management of bark beetles
• Biotic interactions in bark and wood beetles

Main conclusions
The use of attractive molecules from trees or congeners is proving a useful and effective method for trapping native and invasive bark beetles and estimating their infestation levels. These semiochemicals are also important for understanding the interactions between the different species of bark beetles attacking the same trees and eventually manipulate their behavior. This approach could be complemented by visual lures, as shown by cutting-edge research into insect vision. Innovative detection methods are being developed, such as smart traps and trained sniffer dogs.

Climate change, and more particularly warmer temperature and more severe droughts, have been confirmed as a major factor in increasing tree vulnerability to bark and wood borer attacks and must be incorporated into predictive models.

Invasive bark beetle species continue to spread worldwide, taking advantage of bridgeheads to spread from country to country. They can carry pathogenic fungi, increasing the risks to forest health.

Participants will meet again in Stockholm next year at the XXVI IUFRO World Congress to continue discussing these issues.