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ARS Home » Research » Publications at this Location » Publication #114831
Title: IDENTIFICATION OF TWO POWDERY MILDEW FUNGI, OIDIUM NEOLYCOPERSICI SP NOV. AND OIDIUM LYCOPERSICI, INFECTING TOMATO IN DIFFERENT PARTS OF THE WORLD

Author
item KISS, LEVENTE - BUDAPEST HUNGARY
item COOK, ROGER - YORK UK
item SAENZ, GREGORY - UNIV. OF NEW MEXICO
item CUNNINGTON, JAMES - YORK, UK
item TAKAMATSU, SUSUMU - TSU JAPAN
item PASCOE, IAN - VICTORIA AUSTRALIA
item BARDIN, MARC - INRA FRANCE
item NICOT, P - FRANCE
item SATO, Y - TOYAMA JAPAN
item Rossman, Amy

Submitted to: Mycological Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: Emerging and re-emerging diseases are increasingly causing damage to agricultural crops around the world. One such disease is a powdery mildew of tomato that has devastated tomato production particularly in greenhouses. It has spread rapidly around the world and has now been reported throughout Europe and North America. The organism causing tomato powdery mildew is a fungus that has been difficult to identify. Only one similar powdery mildew was known on tomato reported only from Australia. All available specimens of tomato powdery mildew were examined microscopically and living isolates were used to determine the molecular characteristics of this fungus. It was discovered that this emerging disease is caused by a previously unknown fungus distinct from the fungus in Australia. Both fungi causing tomato powdery mildew are described and illustrated. This research provides an accurate scientific name and description so that plant pathologists can accurately communicate about this disease.

Technical Abstract: A world wide study of the Oidium species causing economic damage on tomato has identified two taxa using classical morphological, scanning electron microscopical (SEM) and molecular phylogenetical criteria. A total of 24 tomato powdery mildew isolates and 29 herbarium specimens obtained from all the continents wherever tomatoes are grown were examined. A taxon with non-catenate conidia widespread in Europe, Africa, North and South America and Asia was identified as an O. subgen. Pseudoidium species (teleomorph: Erysiphe sp.). Formerly referred to O. lycopersicum (or O. lycopersici), it is now renamed O. neolycopersici. Only a taxon with catenate conidia was found on Australian specimens. This was identified as a species of O. subgen. Reticulodium (teleomorph: Golovinomyces sp.). Being the most likely contender for O. lycopersicum, it is here neotypified as O. lycopersici.