Downy mildew of the beet, caused by Peronospora schacktii Fuckel

Field experiments on sugar‐beet downy mildew (Peronospora farinosa)

“…Downy mildew of sugar-beet caused by Peronospora farinosa betae (Byford, 1967) causes losses in most seasons in areas of England where sugar-beet root crops are grown near seed crops of sugar beet or mangolds (Byford & Hull, 1967), and attempts to control it with fungicide sprays have given uneven results (Byford, 1966). The symptoms of the disease were fully described by Kuhn (1872) Leach (1931) and Singalovsky (1937) and recovery of affected plants has also been recorded. Stirrup, Hull, Petherbridge & Stapley (1937) and Mollerstrom (1955) say that this takes place in dry weather unfavourable to the fungus, but Darpoux, DurgCat & Lebrun (1960) say that recovery does not depend on weather.…”

“…Rate of appearance of new infections with downy mildew in field trials at Dunholme, Lincs. (1961) and Broom's Barn, Suffolk (1963,1964) Previous workers (Leach, 1931 ;Singalovsky, 1937;Mollerstrom, 1955 ;DurgCat, 1962 andCornford, 1954) reported that seedlings were most susceptible to infection from artificial inoculation at the cotyledon stage, with susceptibility rapidly decreasing thereafter. T h e natural outbreaks of downy mildew at Dunholme and Broom's Barn did not show a rapid initial increase corresponding to maximum susceptibility at the cotyledon stage, and spread continued steadily though slowly for 7-2 up to 15 weeks.…”

Effect of downy mildew on productivity of sugar beets, and selection for resistance

“…HiZgardia [Vol. 16,No.7 was destroyed (4). Downy mildew has also been reported on garden beets in Oregon and Washington and observed at times on sugar beets in Colorado.…”

“…SAssociate Professor of Plant Pathology and Associate Plant Pathologist in the Experiment Station. 4. Italic numbers in parentheses refer to "Literature Cited," at the end of this paper.…”

Some observations on the economic importance of sugar‐beet downy mildew in England

“…Oospores have been recorded by many workers (Prilleux, 1882 ;Darpoux & DurgCat, 1962;Singalovsky, 1937;Cornford, 1958). Leach (1931) reported two infected seedlings when seed was germinated in soil containing oospore-bearing leaf material, and Van der Spek (1964) claimed that, in Holland, oospores are the most important source of primary infections in the seed-growing areas.…”