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Dept for Environment Food and Rural Affairs

Answer

Mr. Lidington: To ask the Secretary of State for Environment, Food and Rural Affairs what assessment she has made of the threat to (a) alders and (b) willows by phytophthora infections; how that assessment is influencing her policy; and if she will make a statement. [61601] Mr. Morley: [holding answer 19 June 2002]: Phytophthoras are a group of microscopic fungal pathogens responsible for plant diseases in many parts of the world. While some cause severe damage, including death of trees, others are of little consequence. The Phytophthora disease of alder is present in England, Scotland and Wales and is most active in the south-west and south-east of England. Surveys of the disease in 2000 and 2001 established that an estimated 600,000 trees were affected: around 12 to 14 per cent. of the alder population. Researchers at the Forestry Commission Research Agency (FCRA) have established that the cause of the disease is a new hybrid pathogen which is very damaging to alder. The putative parents cause little or no damage to alder but can be aggressive pathogens of other woody hosts. In addition to the UK, the disease is present in 10 other European countries. Movement of infected plants has probably facilitated its rapid dissemination and infected stock may start new foci of infection when planted out. Research is continuing to further improve methods of managing the disease and diagnosing the pathogen. As with most Phytophthoras, control is difficult and eradication from already infected riparian habitats would be impossible. As this particular disease is so widespread, quarantine controls would be ineffective. It is rare for willows to suffer from disease caused by species of Phytophthora and they do not appear to be susceptible to the new hybrid Phytophthora that causes disease of alder.

Secondary information

Type

Written question

Reference

387 c924W;387 c921-2W; 61601

Session

2001-02

Subjects

Diseases Disease control Trees Phytophthora ramorum

Contains statistics

Yes

Link

View this Written question on www.publications.parliament.uk