Phytophthora cinnamomi . [Descriptions of Fungi and Bacteria

Abstract

Abstract A description is provided for Phytophthora cinnamomi . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Ananas, Cinchona, Cinnamomum, Castanea, Erica, Persea, Pinus, Rhododendron , and over 100 othor host species including beech, oak, walnut, conifers, avocado, pineapple, cinnamon, Erica , rhododendron, Lawson cypress, English walnut, Irish yew, Douglas fir (Thorn & Zentmyer, 1954, Rangaswami, 1962 and Herb. IMI). DISEASES: Causes 'ink' disease of chestnut in conjunction with P. cambivora and also root rot of many other trees, beech, oak, walnut and conifers, both in the nursery and forest, avocado root rot, pineapple root and heart rot, stripe canker of cinnamon, Erica wilt, root rot of rhododendron and many other ornamentals. GEOGRAPHICAL DISTRIBUTION: World-wide. (CMI Map 302, ed. 2, 1963.) TRANSMISSION: Soil-borne. Persisting up to 10 yr. in naturally infested soil planted with macadamia and avocado seedlings, and remaining viable in dead avocado roots stored in soil for 6 yr. at 20% moisture at 20°C. (Zentmyer & Mircetich, 1963). Soil maybe penetrated to a depth of 2-4 feet (34: 4). Movement of nursery plants with infested soil adhering to their roots may also spread the pathogen (3: 245). Soils with poor drainage and a high moisture level or variable water table favour the pathogen (45, 3027; 42: 162; 34: 4) and zoospores may be disseminated by movement of soil water (41: 490; 43, 2753). Phytophthora cinnamomi may also be seed-borne in seed derived from wind-fallen fruit which has become infected from contact with infested soil (Durbin et al. , 1957).