Pathogenicity of Phytophthora austrocedrae on Austrocedrus chilensis and its relation with "Mal del Ciprés" in Patagonia

GRESLEBIN, A. G.; HANSEN, E.M.

PLANT PATHOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2010 vol. 59 p. 604 - 612

0032-0862

Field observations, isolations and pathogenicity tests were performed on Austrocedrus chilensis (Cupressaceae) trees to determinethe pathogenicity of Phytophthora austrocedrae and its role in the aetiology of the cypress disease mal del cipre´s(MDC) in Argentina. It was found that P. austrocedrae is a primary pathogen of A. chilensis. It was isolated from largenecrotic lesions in the inner bark, and superficially in the sapwood, at the root collar and stem, in most of the MDC-affectedstands surveyed along the range of A. chilensis in Argentina. The main symptom in naturally infected trees was a necroticlesion extending from killed roots up to 1 m up the tree bole. Seedlings, saplings and adult trees were all susceptible to inoculationwith P. austrocedrae. Under favourable experimental conditions (flooding), inoculated seedlings suffered massive mortalityin less than a month. The importance of diseases caused by Phytophthora spp. in South American forests is discussed.