Pythiaceous fungi on citrus

Abstract

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.