Phytophthora lateralis

 

revision

Date de publication

jeu, 30 Jui 2022, 14:59

Dernière mise à jour effectuée le

juin 30, 2022, 2:59 après-midi

Report Number

GBR-25/2

Pays

United Kingdom

Identité de l'organisme nuisible

Phytophthora infestans - (PHYTIN)

Situation du signalement

Final

Hôtes

Chamaecyparis lawsoniana – Lawson cypress

Pest Status (old values from ISPM 8 -1998 )

• Present: under eradication

Pest Status (ISPM 8 - 2021)

• Present: not widely distributed and under official control

Distribution géographique

First found in Scotland in November 2010 and subsequently in another location in Scotland in March 2011. Further findings in Northern Ireland, north-east and south-west England in 2011.

Résumé

Dieback and mortality of Chamaecyparis lawsoniana – Lawson cypress within three areas on the same site totalling 21 symptomatic or dead trees were observed. The affected trees showed similar symptoms to the first finding of Phytophthora lateralis in Scotland (reported March 2011). Five trees had fresh basal lesions and yielded a positive test for Phytophthora with a Lateral Flow Device (LFD). Positive samples were then tested further using Phytophthora-specific PCR primers which were tested on DNA extracted from bark. Resulting sequences were analysed to determine Phytophthora species.

Bark samples from 3 trees gave 100% and 99% sequence matches to Phytophthora lateralis.

Culturing from the material yielded an isolate which was confirmed as P. lateralis based on culture morphology and DNA ITS analysis. Dieback and mortality of 3 Chamaecyparis lawsoniana – Lawson cypress and 2 Chamaecyparis nootkatensis – Nootka cypress were observed.

The affected trees also showed similar symptoms to the first finding, some having fresh basal lesions yielding a positive test for Phytophthora with a Lateral Flow Device (LFD). One tree had branch dieback. Positive samples were then tested further using Phytophthora-specific PCR primers which were tested on DNA extracted from bark. Resulting sequences were analysed to determine Phytophthora species. One isolate from C. lawsoniana gave 100% and 99% sequence matches to Phytophthora lateralis.

Culturing from the material yielded an isolate which was confirmed as P. lateralis based on culture morphology and DNA analysis.

On the same site there were 2 positive identifications for Phytophthora cambivora made on Chamaecyparis lawsoniana and 1 positive identification for Phytophthora austrocedrae made on Chamaecyparis nootkatensis.

There were further findings in 2011 in Northern Ireland, then in south-west England and then in north-east England.

Danger

None - outbreaks are contained and plants destroyed. Measures are being taken to prevent movement of the pathogen from the areas in which infection was found

Fichiers de rapports

Site web

http://www.forestry.gov.uk/newsrele.nsf/WebPressReleases/8C99E845618604C1802578690057238B

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