Onion downy mildew
AuthorC. E. Yarwood
Author AffiliationsC. E. Yarwood was Assistant Professor of Plant Pathology and Assistant Plant Pathologist in the Experiment Station.
Hilgardia 14(11):595-691. DOI:10.3733/hilg.v14n11p595. February 1943.
Abstract does not appear. First page follows.
Downy mildew of onion, caused by Peronospora destructor Berk., is the most important disease of the onion seed crop in California. It is serious on onions grown for bulbs and greens not only here but also in other onion-growing regions throughout the world. Though the disease probably occurs in most regions every year, severe losses are rather sporadic, as is the case with many diseases caused by downy mildews. Most previous attempts to devise control methods for the disease have been unsuccessful. The present study was started in 1935 and is devoted to various biological aspects of the disease and to its control. The work was done in the greenhouse in Berkeley unless otherwise mentioned. The principal literature concerning onion mildew is briefly reviewed, more attention being given to the controversial aspects. Most field observations were made on onions grown for seed, and generalizations in this paper refer to and are based on the California seed crop.
California grows from about 1,000 to 7,000 acres of onions for seed annually (72)3 with a production of perhaps 300,000 to 1,500,000 pounds and a value of perhaps $300,000 to $1,000,000 (no official estimates available). From 1918 to 1929 (72) California produced about 95 per cent of the total onion seed for the United States. Since then, partly because of destructive onion-mildew epidemics in California, some of the seed industry has been moved to Oregon and Idaho. The California bulb crop, varying from about 5,000 to 10,000 acres, produces about 1,000,000 to 1,5001,000 sacks at a value of about $1,000,000 to $1,800,000 (7). California produced about 9 per cent of the total United States crop of onion bulbs during 1935 to 1940.
 Berkeley M. J. Botrytis destructor n. s. In: Notices of British fungi. Ann. Nat. Hist. (ser. 1). 1841. 6:436
 Berkeley M. J. Outlines of British fungology. 1860. London: L. Reeve. 442p.
 Briquet J. International rules of botanical nomenclature. 1935. 3d ed. Jena: Gustav Fischer. 151p.
 Brown E. Preserving the vitality of Bermuda onion seed. Science. 1939. 89:292-93. DOI: 10.1126/science.89.2309.292-a [CrossRef]
 Byers H. R. Summer sea fogs of the central California coast. Univ. California Pubs., Geog. 1930. 3:291-338.
 Caldwell R. M., Stone G. M. Relation of stomatal function of wheat to invasion and infection by leaf rust (Puccinia triticina). Jour Agr. Res. 1936. 52:917-32.
 California Crop Reporting Service. Truck crop notes 255 1937. p.2. January 4. (Mimeo.)
 California Crop Reporting Service. Commercial vegetable crops, California 1938. p.25. May. (Mimeo.)
 Chapman G. H. Notes on the occurrence of fungous spores on onion seed. Massachusetts Agr. Exp. Sta. Ann. Rept. 1910. 22:164-67.
 Chou C. L. [Notes on fungous diseases in China.] [In Chinese.]. Khu Shou [Science]. 1919. 4:1223-29.
 Clements F. E., Shear C. L. The genera of fungi. 1931. New York, N. Y.: The H. W. Wilson Co. 496p.
 Cook H. T. Studies on the downy mildew of onions, and the causal organism Peronospora destructor (Berk.) Caspary. N. Y. (Cornell) Agr. Exp. Sta. Mem. 1932. 143:1-40.
 De Bary A. Recherches sur le développement de quelques champignons parasites. Ann. des Sci. Nat., Bot. (ser. 4). 1863. 20:122
 Doran W. L. Downy mildew of cucumbers. Massachusetts Agr. Exp. Sta. Bul. 1932. 283:1-22.
 Doran W. L., Bourne A. I. Onion spraying and dusting experiments. Massachusetts Agr. Exp. Sta. Bul. 1931. 279:176-85.
 Dudley W. R. The onion mould. N. Y. (Cornell) Agr. Exp. Sta. Bul. 1899. 15:193-95.
 Duggar B. M. Fungous diseases of plants. 1909. Boston, Mass.: Ginn and Company. 508p.
 Edgerton C. W. Onion diseases and onion seed production. Louisiana Agr. Exp. Sta. Bul. 1921. 182:1-20.
 Finland. Gesetze und Verordnungen. Finnland. Nachrichtenbl. f. den Deut. Pflanzensehutzdienst. 1925. 5:106 Abstracted in: Rev. Appl. Mycol. 5: 190. 1926.
 Fitzpatrick H. M. The lower fungi. Phycomycetes. 1930. New York, N. Y.: McGraw-Hill Book Co., Inc. 331p.
 Fuckel L. Symbolae mycologicae. Beiträge zur Kenntnis der Rhenischen Pilze. Nassau. Ver. f. Naturk. Jahrb. 1870. 23-24:1-459.
 Gaümann E. Beiträge zu einer Monographie der Gattung Peronospora Corda. Beitr. z. Kryptogamenflora der Schweiz. 1923. 5:1-360.
 Great Britain Ministry of Agriculture and Fisheries. Reports of the work of agricultural research institutes and on certain other agricultural investigations in the United Kingdom. 1932. London: H. M. Stationary Office. 377p.
 Hearst W. H. Vegetable specialist. Ontario Min. Agr. Rept. 1918. 1917:60-62.
 Hiura M. Studies on some downy mildews of agricultural plants. IV. On the downy mildew of the Welsh onion. (Report I.) Byôchû-Gai Zasshi. (Jour. Plant Protect.) [Tokyo] 1930. p.10. Abstracted in: Rev. Appl. Mycol. 10: 7. 1931.
 Hiura M. Studies on some downy mildews of agricultural plants. IV. On the downy mildew of the Welsh onion. (Report II.) Agr. and Hort. [Tokyo]. 1930. 5:1008-14.
 Hoagland D. R., Snyder W. C. Nutrition of the strawberry plant under controlled conditions. Amer. Soc. Hort. Sci. Proc. 1933. 30:288-94.
 Jones H. A., Emsweller S. L. Effect of storage, bulb size, spacing, and time of planting on the production of onion seed. California Agr. Exp. Sta. Bul. 1939. 628:1-14. https://archive.org/details/effectofstorageb628jone
 Jones H. A., Porter D. R., Leach L. D. Breeding for resistance to onion downy mildew caused by Peronospora destructor. Hilgardia. 1939. 12(9):531-50. DOI: 10.3733/hilg.v12n09p531 [CrossRef]
 Jones L. R. The onion mildew. Vermont Agr. Exp. Sta. Ann. Rept. 1897. 10:61-62.
 Katterfeld N. O. K eiologii Peronospora schleideni Ung. (Zur biologie der Peronospora schleideni Ung.). [In Russian; German summary.]. Bolezni Rastenií (Morbi Plantarum). 1926. 15:71-87.
 Kirk T. W. Onion mildew. New Zealand Dept. Agr. Ann. Rept. 1905. 13:415-16.
 Kunkel O. The influence of starch, peptone, and sugars on the toxicity of various nitrates to Monilia sitophila (Mont.). Sacc. Torrey Bot. Club Bul. 1913. 40:625-39. DOI: 10.2307/2479464 [CrossRef]
 Lindquist J. C. Especies argentinas del genero “Peronospora.”. Rev. Soc. Argentina de Cien. Nat. 1939. 15:13-20.
 McCallum W. B. Some common plant diseases. Arizona Agr. Exp. Sta. Timely Hints for Farmers. 1908. 76:1-7.
 McKay Robert. Observations on onion mildew caused by the fungus Peronospora Schleideniana W. G. Sm. Roy. Hort. Soc. Jour. 1939. 64:272-85.
 McWhorter Frank P. Onion mildew. Oregon Agr. Exp. Sta. Cir. 1936. 131:1-2.
 McWhorter Frank P., Pryor John. Onion mildew in Oregon and the advisability of testing malachite green as a control agent for downy mildews. Plant Dis. Reporter. 1937. 21:306-7. (Mimeo.) [Issued by U. S. Bur. Plant. Indus.]
 Massee G. M. A text-book of plant diseases. 1907. New York, N. Y.: The Macmillan Co. 472p.
 Massee G., Crossland C. The fungus flora of Yorkshire. Yorkshire Naturalists’ Union Trans., part 32 1905. Original not seen, cited by Gaümann, citation 22
 Milbrath D. G. Plant pathology. California State Dept. Agr. Mo. Bul. 1926. 15(7-12):131-33.
 Muncie J. H. Onion growers profit by seed and soil treatment. Ext. Path. 1937. 30:53-54. (Mimeo.)
 Murphy Paul A. The presence of perennial mycelium in Peronospora Schleideni Unger. Nature [London]. 1921. 108:304 DOI: 10.1038/108304a0 [CrossRef]
 Murphy Paul A., McKay Robert. The downy mildew of onions (Peronospora Schleideni) with particular reference to the hibernation of the parasite. Roy. Dublin Soc. Sci. Proc. 1926. 18:237-61.
 Murphy Paul A., McKay Robert. Some new facts concerning onion mildew. [Irish Free State] Dept. Lands Agr. Jour. 1926. 26:115-23.
 Murphy Paul A., McKay Robert. Further observations and experiments on the origin and control of onion mildew. [Irish Free State] Dept. Agr. Jour. 1932. 31(1):60-76.
 Newhall A. G. Onion mildew prevalent in New York. Plant Dis. Reporter [Issued by U. S. Bur. Plant Indus.]. 1935. 19:234 (Mimeo.)
 Newhall A. G. They did it themselves 1938. How the township of Marion, N. Y. licked onion blight. Amer. Agr. December 17.
 Newhall A. G. The spread of onion mildew by wind-borne conidia of Peronospora destructor. Phytopathology. 1938. 28:257-69.
 Newhall A. G. Progress in control of onion mildew (Peronospora destructor) in New York. [Abstract.] Phytopathology. 1939. 29:18
 New South Wales Department of Agriculture. Plant diseases (cont.). Downy mildew of onions. Agr. Gaz. N. S. Wales. 1939. 50:623-24.
 Osmun A. V. Onion blight or downy mildew. Massachusetts Agr. Exp. Sta. Bul. 1926. 227:46-47.
 Owens C. E. Principles of plant pathology. 1928. New York, N. Y.: John Wiley and Sons, Inc. 629p.
 Rawlins T. E. Phytopathological and botanical research methods. 1933. New York, N. Y.: John Wiley and Sons, Inc. 156p.
 Rhitzema Bos J. Ziekte der sjalotten veroorzaakt door Peronospora Schleideni Unger en Macrosporium Parasiticum Thumen. Tijdschr. over Plantenziekten. 1898. 4:10-16.
 Saccardo P. A. Sylloge Fungorum. 1888. 7:244-45. 257.
 Scalia G. Fungi della Sicilia orientale e principalemente della regione Etnea. Atti Accad. Gioenia Sci. Nat. Catania 78, Mem. 1900. 20:1-55. (Original not seen, cited by E. Gaümann, citation 22
 Schleiden M. J. Grundzüge der Wissenschaftlichen Botanik, Zweiter Theil. 1846. Leipzig: Engelmann. 614p.
 Schoyen W. M. In Norwegen in Jahre 1899 aufgetretene Krankheitserscheinungen. Ztschr. f. Pflanzenkrank. 1901. 11:104-8.
 Shipley A. Onion disease at Bermuda. Kew Roy. Bot. Gard. Bul. Misc. Inform. 1887. 10:1-23.
 Smith Ralph E. Onion mildew investigation. Report of the plant pathologist and superintendent of southern California stations. 1909. 203:39 July 1, 1906, to June 30, 1909. California Agr. Exp. Sta. Bul.
 Smith Worthington G. Diseases of field and garden crops. 1884. London: The Macmillan Co. 353p.
 Stevens N. E. A method for studying the humidity relations of fungi in culture. Phytopathology. 1916. 6:428-32.
 Sutton and Sons. The culture of vegetables and flowers. 1936. 19th ed. London: Simpkin Marshall, Ltd. 458p.
 Taubenhaus J. J. Leaf blight of onions. Texas Agr. Exp. Sta. Ann. Rept. 1934. 47:95
 Thaxter R. The onion mildew. Connecticut Agr. Exp. Sta. Ann. Rept. 1890. 1889:155-58.
 Thuemen F. V. Verzeichnis der in Bayreuth in Oberfranken beobachten Pilze. Siebenter Ber. Bot. Ver. Landshut. 1879. pp.167-212. (Original not seen, cited by. E. Gaümann, citation 22
 Treboux O. Verzeichnis parasitischer Pilze aus dem Gouvernment Charkow. Kharkow Univ. Trav. Soc. Nat. 1913. 46:1-16.
 Trelease W. The onion mould. Wisconsin Agr. Exp. Sta. Ann. Rept. 1884. 1883:38-44.
 Unger D. F. Botanische Beobachtungen. Bot. Ztg. 1847. 5:303-18.
 United States Department of Agriculture Marketing Service. Results of recent vegetable seed survey show larger 1940 production but smaller carry-over 1941. p.2. January. (Mimeo.)
 United States Bureau of Agricultural Economics. Seed statistics 1936. p.58. May. (Processed.)
 Verwoerd L., Du Plessis S. J. Descriptions of some new species of South African fungi and of species not previously recorded in South Africa. III. So. Africa Jour. Sci. 1931. 28:290-97.
 Wakefield E. M., Moore W. C. Notes on certain changes in nomenclature in the second edition of the list of common names of British plant diseases. Brit. Mycol. Soc. Trans. 1936. 20:97-109. DOI: 10.1016/S0007-1536(36)80001-1 [CrossRef]
 Walker J. C. Observations on the cultivation and diseases of cabbage and onions in Europe. Plant Dis. Reporter Sup. [Issued by U. S. Bur. Plant Indus.]. 1924. 32:1-34. (Mimeo.)
 Whetzel H. H. Onion blight. N. Y. (Cornell) Agr. Exp. Sta. Bul. 1904. 218:138-61.
 Wilson G. W. Studies in North American Peronosporales—VI. Notes on miscellaneous species. Mycologia. 1914. 6:192-210.
 Yarwood C. E. Downy mildew of onion in California. Plant Dis. Reporter [Issued by U. S. Bur. Plant Indus.]. 1935. 19:254-55. (Mimeo.)
 Yarwood C. E. The relation of light to the diurnal cycle of sporulation of certain downy mildews. Jour. Agr. Res. 1937. 54(5):365-73.
 Yarwood C. E. Sulphur and rosin as downy mildew fungicides. Phytopathology. 1937. 27:931-41.
 Yarwood C. E. Botrytis infection of onion leaves and seed stalks. U. S. Bur. Plant Indus.]. 1938. 22:428-29. (Mimeo.) Plant Dis. Reporter [Issued by
 Yarwood C. E. Further tests of rosin-lime sulphur as a fungicide. [Abstract.] Phytopathology. 1938. 28:22
 Yarwood C. E. The fungicidal value of cottonseed oil and some other spray supplements. [Abstract.] Phytopathology. 1939. 29:24
 Yarwood C. E. Relation of moisture to infection with some downy mildews and rusts. Phytopathology. 1939. 29:933-45.
 Yarwood C. E. Sporulation injury associated with downy mildew infections. Phytopathology. 1941. 31:741-48.
 Yoshino D. List of fungi found in the province of Higo. [In Japanese.] Bot. Mag. [Tokyo]. 1905. 19:87 103, 199, 222.
 Zimmerman H. Verzeichnis der Pilze aus der Umgebung von Eisgrub. II. Teil. Naturf. Ver. in Brünn, Verhandl. 1914. 52:62-128.
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