University of California

Breeding for resistance to onion downy mildew caused by Peronospora destructor


H. A. Jones
D. R. Porter
L. D. Leach

Authors Affiliations

H. A. Jones was Principal Olericulturist, United States Department of Agriculture Bureau of Plant Industry, Division of Fruit and Vegetable Crops and Diseases; D. R. Porter was Associate Professor of Truck Crops and Associate Olericulturist in the Experiment Station; resigned January 1, 1939; L. D. Leach was Assistant Professor of Plant Pathology and Assistant Plant Pathologist in the Experiment Station.

Publication Information

Hilgardia 12(9):531-550. DOI:10.3733/hilg.v12n09p531. October 1939.

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The onion downy-mildew fungus, Peronospora destructor (Berk.) Casp., is practically world-wide in distribution (2), (5).5 It was first described in 1841 by Berkeley (1) in England, and reported by Trelease (12) from Wisconsin in 1884. Subsequently it has been found in a number of other states and has frequently assumed epidemic proportions.

Because adequate control measures have not been developed, the disease continues to cause losses of varying magnitude. Such losses are usually most severe under conditions of moderate temperature and high humidity.

Even though recent work by Yarwood (14), (15) and by McWhorter and Pryor (7) indicates the fungicidal efficacy of certain chemical mixtures, the more satisfactory means of prevention involves the development of disease-resistant varieties. In this paper are presented data relative to varietal reaction to mildew, discussion of resistant types that have been found, and the present status of the breeding work designed to transmit resistance to varieties of commercial importance. The studies were made at Davis, California, and at other experimental tracts, as mentioned in the text.

Literature Cited

[1.] Berkeley M. J. Botrytis destructor, n. s. Notices of British fungi. Ann. and Mag. Nat. Hist. 1841. 6:436

[2.] Cook H. T. Studies on the downy mildew of onions, and the causal organism, Peronospora destructor (Berk.) Caspary. New York (Cornell) Agr. Exp. Sta. Mem. 1932. 143:1-40.

[3.] Jones H. A., Bailey S. F., Emsweller S. L. Thrips resistance in the onion. Hilgardia. 1934. 8(7):215-32. DOI: 10.3733/hilg.v08n07p213 [CrossRef]

[4.] Jones H. A., Emsweller S. L. A male sterile onion. Amer. Soc. Hort. Sci. Proc. 1936. 34:582-85.

[5.] McKay Robert. Germination of resting spores of onion mildew. Nature (London). 1935. 135:306 DOI: 10.1038/135306b0 [CrossRef]

[6.] McKay Robert. Germination of oöspores of onion mildew, Peronospora schleideniana W. G. Sm. Nature (London). 1937. 139:758-59.

[7.] McWhorter F. P., Pryor John. Onion mildew in Oregon and the advisability of testing malachite green as a control agent for downy mildews. U. S. Dept. Agr. Bur. Plant Ind. Plant Disease Reporter. 1937. 21:306 (Mimeo.)

[8.] Murphy Paul A., McKay Robert. The downy mildew of onions (Peronospora schleideni) with particular reference to the hibernation of the parasite. Royal (Dublin) Soc. Sci. Proc. 1926. 18(1924-1928):237-61.

[9.] Murphy P. A., McKay R. Further observations and experiments on the origin and control of onion mildew. Irish Free State Dept. Agr. Jour. 1932. 31(11):60-76.

[10.] Newhall A. G. The spread of onion mildew by wind-blown conidia of Peronospora destructor. Phytopathology. 1938. 28:257-69.

[11.] Stuart W. W., Newhall A. G. Further evidence of the seed borne nature of Peronospora destructor. [Abstract.] Phytopathology. 1935. 25:35

[12.] Trelease Wm. The onion mold. Wisconsin Agr. Exp. Sta. Ann. Rept. 1884. 1(1883):38-44.

[13.] Yarwood C. E. The relation of light to the diurnal cycle of sporulation of certain downy mildews. Jour. Agr. Research. 1937. 54(5):365-73.

[14.] Yarwood Cecil E. Sulphur and rosin as a downy mildew fungicide. Phytopathology. 1937. 27(9):931-41.

[15.] Yarwood Cecil E. Further tests of rosin-lime sulphur as a fungicide. [Abstract.] Phytopathology. 1938. 28(1):22

Jones H, Porter D, Leach L. 1939. Breeding for resistance to onion downy mildew caused by Peronospora destructor. Hilgardia 12(9):531-550. DOI:10.3733/hilg.v12n09p531

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