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The DED in Australia: control and risk of spreading

During the third "international elm conference", held in Florence in October, we met Greg Lefoe, a researcher at  the Department of Environment and Primary Industries in Melbourne. Australia has a longstanding association with elms. Elms were imported from the early 1800's, and became a fundamental part of the urban landscape in many cities. DED is not present in Australia, and Greg works with colleagues and community groups to reduce the risk of introduction of the disease to his country. His presence at the conference Florentine was funded by a group of volunteers called "Friends of the Elms Inc". We asked him, with curiosity, some information on the control of risk of introduction of DED in Australia.

Greg Lefoe in Florence, during the international elm conference
Mr. Lefoe, what is the situation of DED in your country?   
Australia has a strong quarantine barrier, and there are no DED pathogens established in Australia. So we're very fortunate, as we still have many large, mature European elms in our avenues, parks and gardens. However we need to remain vigilant for a number of reasons: 
- a large proportion of our elms, such as Ulmus procera , U. X hollandica and U. glabra cultivars are susceptible to Ophiostoma ulmi  and O. novo-ulmi,
- the smaller European elm bark beetle Scolytus multistriatus is established and widespread on mainland Australia, 
- DED is now established in New Zealand, one of Australia's closest neighbours. 

How is it controlled the introduction of the bark beetle vector of DED in Australia?
In the absence of DED pathogens the bark beetle is considered a minor pest, and tree managers keep bark beetle populations low by maintaining healthy trees. However the bark beetles pest status would rapidly change if the fungus was introduced. A DED Contingency Plan was prepared in 2001 with recommendations to reduce the vulnerability of Australia's elm population, prevent the introduction of DED pathogens, and guidelines on how to detect and respond to an incursion if it should occur. 

There are plantations with new varieties of elm in an urban environment?

There are not many DED-resistant elms available in Australia, and susceptible trees are still used to replace aging elms.There are nurseries that sell DED-resistant elms such as Ulmus "Sapporo Autumn Gold". I think there would be interest in elms that have resistance to both DED and elm leaf beetle (Xanthogaleruca luteola), which is a damaging pest in Australia. 
 


At the Third International Elm Conference, we asked Greg Lefoe, a researcher at "University of Melbourne", some information on the management of the elm trees in Australia

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