Three New Races of the Spinach Downy Mildew Pathogen Identified by a Modified Set of Spinach Differentials
Open Access
- 1 November 2007
- journal article
- Published by Scientific Societies in Plant Disease
- Vol. 91 (11), 1392-1396
- https://doi.org/10.1094/pdis-91-11-1392
Abstract
Spinach downy mildew, caused by Peronospora farinosa f. sp. spinaciae, is the most economically important disease of spinach worldwide. During the past few years, spinach cultivars resistant to the seven previously described races of P. farinosa f. sp. spinaciae were observed to be severely affected by downy mildew in both the United States and the European Union. Four new isolates of P. farinosa f. sp. spinaciae were collected from California and The Netherlands and characterized based on disease reactions on two modified sets of spinach differentials. The results led to the description of three new races of the downy mildew pathogen, designated races 8, 9, and 10. Four differential cultivars with resistance to races 1 to 7 were used to distinguish the three new races. Dolphin was susceptible to races 8 and 10 but resistant to race 9; Lion was susceptible to race 10 but resistant to races 8 and 9; Lazio was resistant to races 1 to 7 as well as races 8, 9, and 10; and Tarpy was susceptible to all three new races. The three new races also were used to evaluate the disease reactions on 43 contemporary commercial spinach cultivars in greenhouse trials. A survey of 58 isolates of P. farinosa f. sp. spinaciae collected in California and Arizona between 2004 and 2006 revealed that race 10 predominated in the areas sampled.Keywords
This publication has 14 references indexed in Scilit:
- Appearance of race Pfs:5 of spinach downy mildew fungus, Peronospora farinosa f. sp. spinaciae, in JapanJournal of General Plant Pathology, 2006
- First Report of Peronospora farinosa f. sp. spinaciae Race 5 Causing Downy Mildew on Spinach in FloridaPlant Disease, 2004
- Identification and Cultivar Reaction to Three New Races of the Spinach Downy Mildew Pathogen from the United States and EuropePlant Disease, 2003
- Characterization of Resistance of Spinach to White Rust (Albugo occidentalis) and Downy Mildew (Peronospora farinosaf. sp.spinaciae)Phytopathology®, 1994
- A New Race (Race 4) of Spinach Downy Mildew in ItalyPlant Disease, 1994
- Economically Important Diseases of SpinachPlant Disease, 1994
- Identification of and Cultivar Reactions to a New Race (Race 4) ofPeronospora farinosaf. sp.spinaciaeon Spinach in the United StatesPlant Disease, 1991
- Seed Transmission of Spinach Downy MildewPlant Disease, 1983
- Occurrence of Race 3 ofPeronospora effusaon Spinach in Texas and Identification of Sources of ResistancePlant Disease, 1982
- Linkage in Spinacia oleracea L. of two race-specific genes for resistance to downy mildew Peronospora farinosa f. sp. spinaciaeByfordEuphytica, 1976