Pythiaceous fungi on citrus

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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.