Context

Sweet chestnut blight (Cryphonectria parasitica) is a destructive disease of sweet chestnut trees (Castanea genus) caused by Cryphonectria parasitica. The fungus originated in eastern Asia where it occurs on indigenous sweet chestnut species but causes little damage because of co-evolution and adaptation. However, the fungus has caused severe epidemics in North America and continental Europe. Since 2011 the fungus has been found on a small number of sites in central and southern England.

This project will develop international collaborations with scientists working in Japan and Switzerland:

• The research with Switzerland will involve staff exchange and collaboration to develop the biological control agent Cryphonectria hypovirus 1 (CHV1) and other potential viruses of Cryphonectria parasitica, including assessment of the best method to apply the biological control agent in affected sites in the UK.
• The work with Japan will involve a visit from the principal investigator to Forest Research to work on newly identified hypoviruses in the new containment facility in Alice Holt. These hypoviruses have been recently detected in Cryphonectria parasitica, and have potential as biological control agents.

Expected outcomes

• Evidence required to develop and implement management programmes for sweet chestnut blight in the UK.
• Identification of new hypoviruses and evaluation as novel biological control agents.