UK/East Anglia: Scientists develop new fungicide in fight against ash dieback disease

Chalara or ash dieback

Chalara or ash dieback - Credit: Archant

A woodland expert has given a cautious welcome to a new fungicide aimed at combating ash dieback disease which was trialled in East Anglia, and which it is hoped could eventually be used to help protect cereal crops as well.

Professor Tony Moore and his team at the University of Sussex developed AOX fungicides to inhibit growth of Chalara fraxinea, which causes ash dieback, and initial trials have been carried out at The Sainsbury Laboratory in Norwich.

As fungal pathogens are adept at developing resistance to treatments through an enzyme called the alternative oxidase (AOX), Professor Moore has formulated a new compound to prevent this enzyme from being functional. If developed, these compounds may be effective for longer and need less frequent spraying.

Tim Woodward, regional surveyor at Country Land and Business Association (CLA) East, described the advance as “interesting and encouraging”.

“Chalara fraxinea was first detected in this region a couple of years ago, but it’s now thought it may have been here for longer. It kills both young and mature trees, and is causing great concern to woodland owners, the woodfuel industry, and the timber industry.

“The fungicide treatment developed at the University of Sussex is an interesting and encouraging development, especially since this region, along with the south-east, is the worst affected so far by chalara, which seems to be spreading outwards from here.

“However, this developmental fungicide may be of limited practical use for our members until more is known, since it seems likely to be most used in nurseries, rather than in existing woodland. It is also more problematic to use fungicides in native woodland, where spraying is difficult and may affect beneficial fungi that help tree nutrition and healthy growth.”

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The compounds were said to be particularly effective when combined with a traditional fungicide that targets a different enzyme in the fungus. Professor Moore and his colleagues identified the current target using data made available by The Sainsbury Laboratory on infected tree samples. The data are available for other scientists to analyse on the crowdsourcing website OpenAshDieBack.

Professor Moore hopes that in the future, AOX fungicides could also be used to better protect cereal crops from pathogenic fungi. As well as protecting yields, they could lessen the environmental damage caused by multiple applications. The University of Sussex is currently working with the Sussex Innovation Centre to help bring the compounds to market, and is seeking commercial partners to develop AOX fungicides for a range of applications.

If developed further, the treatment could be used on infected nursery stock or ash plantations that are blighted by the ash dieback disease. It is more problematic to use fungicides in native woodland, where spraying is difficult and fungicides may affect beneficial fungi that help tree nutrition and healthy growth.

Ash dieback has spread rapidly throughout mainland Europe over the past two decades. The fungus was first reported in Britain in early 2012, and current estimates suggest that between 90-99 per cent of the country’s native ash trees could be killed by the disease.

Ian Carter, Director of Research and Enterprise at the University of Sussex, said: “It’s extremely encouraging to see the successful trials of Professor Moore’s innovation that are coming out of The Sainsbury Laboratory. We’re delighted that research at Sussex is producing such promising results and helping to provide solutions to real global problems.”

Dr Diane Saunders, The Sainsbury Laboratory, said: “This first step in testing the new compounds, on the growth of fungus cultured in the laboratory, was promising. If developed, it could help nursery and plantation owners. It would be particularly useful for protecting trees that are susceptible to the pathogen when young, but which might be more tolerant to it when they are mature. Our own research is focused on both ash trees and the fungus, with the long term goal to develop a way to select and breed trees able to withstand the disease for generations to come.”

The Sainsbury Laboratory at Norwich Research Park is a world-leading research centre focusing on making fundamental discoveries about plants and how they interact with microbes.