University of California

Pythiaceous fungi on citrus


Vincent A. Wager

Author Affiliations

Vincent A. Wager was Plant Pathologist, Union of South Africa Department of Agriculture. On Commonwealth Fellowship in collaboration with the Division of Plant Pathology, University of California Citrus Experiment Station, Riverside, California, September, 1939, to June, 1940.

Publication Information

Hilgardia 14(9):533-548. DOI:10.3733/hilg.v14n09p533. August 1942.

PDF of full article, Cite this article


Abstract does not appear. First page follows.

Pythiaceous fungi on citrus in California were investigated during the season 1939-40. In the course of this investigation, citrus roots were examined for the presence of fungi, inoculation experiments were performed on citrus fruits with pythiaceous fungi from citrus in general, and growth-temperature relations of Phytophthora species found on citrus were studied. This paper reports the results of this work, and includes a compilation of records on the geographic distribution of Phytophthora on citrus and a description of all Phytophthora and Pythium species recorded on citrus.

Pythiaceous Fungi on Roots of Citrus

In previously reported work on the isolation of fungi from roots of citrus, Fawcett (3)4 states that species of Pythium and Phytophthora have been found to be associated with the damping-off and death of young citrus trees. Weindling (11) isolated Phytophthora parasitica Dastur and Pytihium spp. from citrus seedlings affected with this disease in California, and Perlberger (5) found Phytophthora citrophthora (Sm. and Sm.) Leonian and Phytophthora parasitica in the same connection in Palestine. Fawcett (1) recorded the finding of Phytophthora citrophthora and Phytophthora parasiiica in 1923 on large citrus roots and showed that the former would attack small roots of lemon trees. He (2), (3) also found Pythium megasperma Drechsl. on the fibrous roots of orange trees dying back in heavy clay soil in Tulare County, California. In 1935, Petri (6) found Pythium meqalacantlvus de Bary and Pythium de Baryanum Hesse associated with root rot of oranges in Catania, Italy.

Literature Cited

[1] Fawcett Howard S. Gummosis of Citrus. Jour. Agr. Res. 1923. 24:191-236.

[2] Fawcett Howard S. New locations for Phytophthora citrophthora and P. hibernalis on Citrus. Phytopathology. 1933. 23:667-69.

[3] Fawcett Howard S. Citrus diseases and their control 1936. p.656. 2d ed. McGraw-Hill Book Company, Inc., New York, N. Y.

[4] Fawcett H. S., Bitancourt A. A. Occurrence, pathogenicity, and temperature relations of Phytophthora species on citrus in Brazil and other South American countries. Inst. Biol. Arch. 1940. 11:107-18.

[5] Perlberger J. Phytophthora stem and tip blight of Citrus seedlings. Hadar. 1936. 9(6-7):145-50.

[6] Petri L. Pythium megalacanthum Rassegna dei casa fitopatologici osservati nel 1934. [Roma] R. Staz. di Patol. Veg. Bol. 1935. 15:1-95.

[7] Tucker C. M. Taxonomy of the genus Phytophthora de Bary. Missouri Agr. Exp. Sta. Res. Bul. 1931. 153:1-208.

[8] Wager Vincent A. Diseases of plants in South Africa due to members of the Pythiaceae. Union So. Africa Dept. Agr. [Sci.] Bul. 1931. 105:1-43.

[9] Wager Vincent A. The navel-end-rot, splitting, and large-navel-end problems of Washington Navel oranges in the Kat River Valley. Union So. Africa Dept. Agr. Sci. Bul. 1939. 192:1-20.

[10] Wager Vincent A. Phytophthora Cinnamomi and wet soil in relation to the dying-back of avocado trees. Hilgardia. 1942. 14(9):517-32. DOI: 10.3733/hilg.v14n09p517 [CrossRef]

[11] Weindling R. Trichoderma lignorum as a parasite of other soil fungi. Phytopathology. 1932. 22:837-45.

Wager V. 1942. Pythiaceous fungi on citrus. Hilgardia 14(9):533-548. DOI:10.3733/hilg.v14n09p533
Webmaster Email: sjosterman@ucanr.edu