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Improving lives by solving problems in agriculture and the environment

Sentinel nurseries as early warning system against alien tree pests

Many of the alien pests and diseases of woody plants were unknown before they were established in new countries. No policy or measures to avoid their introduction and spread were therefore implemented. Recently, monitoring sentinel plants in exporting countries has been proposed as a valuable tool to identify harmful organisms prior to their arrival. This Action advances the use of sentinel plants through international collaboration of scientists and regulators.

Project Overview

So, what's the problem

Many invasive tree pests and pathogens are introduced to new countries through the international trade in live plants which causes untold environmental and economic damage. Many of these were previously unknown to be harmful, or even to science, and were therefore not regulated before they invaded. This suggests that the current system to identify harmful species doesn’t provide sufficient protection. 

Better knowledge of organisms that may be introduced and harmful to a country would enable them to develop and apply measures to mitigate these risks. 

By monitoring trees planted in regions that export plants, it is possible to identify potentially harmful organisms that need regulation. However, as this is new, the methods, regulations and network required for implementing this promising tool need to be developed further.

What is this project doing?

COST Action Global Warning is establishing a global network of scientists and regulators in countries where sentinel nurseries could be established from propagation material, or where botanical gardens or arboreta with exotic trees already exist. 

We will also develop common protocols for monitoring and identifying pests, as well as explore ways to regulate how these nurseries are established and the data collected by them should be used. 

This Action will bring together detailed information about the international trade in trees and the environmental value of native trees in Europe. 

The Action will produce printed and electronic and workshop outputs, as well as at least five short-term scientific missions per year.

Aspects of the sampling will be investigated by Iva Franic who will help to assess the full range of organisms associated with a tree species or genus. Funded by the Swiss National Science Foundation, Iva is a PhD student at CABI’s centre in Switzerland. Her work, which has close links to the COST Action, is supervised by CABI’s René Eschen and Marc Kenis, as well as Dr Simone Prospero of the Swiss Federal Institute for Forest, Snow and Landscape Research, WSL and Prof Eric Allan of the University of Bern.


The Action has already resulted in several scientific publications and has organised two training schools (about import regulations for plants for planting and pest risk analysis and about classical techniques for fungal identification).

Recently, an open-access identification guide on the damaging agents of woody plants was developed by members of this project from around 25 countries and will be used by practitioners worldwide. 

The team

Project Manager

Staff image of René Eschen

René Eschen  Research Scientist, Ecosystems Management, and Risk Analysis and Invasion Ecology

Rue des Grillons 1 CH-2800 Delémont
T +41 (0)32 421 48 87

Project team

Staff image of Marc Kenis

Marc Kenis

Head Risk Analysis and Invasion Ecology

Staff image of Iva Franić

Iva Franić

PhD student

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