Downy mildew of oilseed poppy (Papaver somniferum) has become a serious disease issue for the Tasmanian poppy industry since its first record in 1996. Previous reports have reported the pathogen as Peronospora arborescens, which is differentiated from the related species P. cristata, also known to infect Papaver spp., by conidium dimensions alone. This study investigated the taxonomic status of the downy mildew pathogen, using both morphological characters and molecular analysis of the internal transcribed spacer (ITS) region of the ribosomal DNA (rDNA). The inherent variability of conidium dimensions made differentiation of species difficult. Sequence homology and phylogenetic analyses of the ITS region showed the pathogen to be more closely related to P. cristata than P. arborescens. It is therefore proposed that downy mildew of oilseed poppy in Tasmania be reattributed to the pathogen P. cristata. In addition to this work, PCR primers have been developed for the specific detection of the downy mildew pathogen in Tasmania.

Item Type:	Refereed Article
Research Division:	Agricultural, Veterinary and Food Sciences
Research Group:	Crop and pasture production
Research Field:	Crop and pasture protection (incl. pests, diseases and weeds)
Objective Division:	Plant Production and Plant Primary Products
Objective Group:	Horticultural crops
Objective Field:	Horticultural crops not elsewhere classified
UTAS Author:	Scott, JB (Dr Jason Scott)
UTAS Author:	Hay, FS (Dr Frank Hay)
UTAS Author:	Wilson, CR (Professor Calum Wilson)
ID Code:	24440
Year Published:	2004
Web of Science® Times Cited:	19
Deposited By:	Agricultural Science
Deposited On:	2004-08-01
Last Modified:	2011-11-22
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