Study says new approaches needed to control spread of pathogens
By Summit Voice
FRISCO — The new infestation of tree-killing emerald ash borers in Boulder is just one symptom of a global trend recently identified by scientists from the universities of Southampton, Cambridge, Oxford and St Andrews.
The findings, published Nov. 15 in the journal Science, suggest that the number of pests and disease outbreaks in trees and forests across the world has been increasing.
There is growing concern that aspects of globalization — in particular, high volumes and new forms of trade — may increase the risk of disease spreading and provide opportunities for genetic re-assortment which can enhance the ability of an organism to cause disease.
Trees and forests provide a wide variety of ecosystem services in addition to timber, food, and other provisioning services, such as carbon sequester and storage, reducing flood risk and leisure use.
The researchers said new approaches to pest and disease management are needed that take into account these multiple services and the different stakeholders they benefit, as well as the likelihood of greater threats in the future resulting from globalisation and climate change.
But identifying all species that may become pests will be impossible, so the researchers stress the importance of trying to control pests along their pathways of introduction, especially where modern trade practices provide potential new routes of entry for pests and pathogens.
Science-based policy and practice can prevent the introduction of new diseases and improve recovery and ongoing management. Proactive measures could include breeding resistant trees and developing of effective bio-control systems.
“Modern pest and disease management for plants and the natural environment needs to be based on an extensive science base,” said Peter Freer-Smith, a visiting Professor in the Centre for Biological Sciences at the University of Southampton. “We need to understand the molecular basis of pathogenicity and herbivores, as well as why some species reach epidemic prevalence and abundance.”
Researchers also examined the difficulties of maintaining tree health and considered the consequences of pests and diseases for the full range of ecosystem services provided by trees. The term “pest” and “disease” was used to describe all pathogens and small-to medium-size insect herbivores that — by causing tree damage and death — disrupt the ecosystem services provided by trees.
Many of the benefits from woodlands and forests, for example carbon storage, maintenance of biodiversity and recreational use, are un-costed and enjoyed by a range of stakeholders. This raises difficult questions about who should be responsible for measures to protect tree health.