Abstract
A description is provided for Phytophthora nicotianae var. nicotianae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Nicotiana plumbaginifolia, N. tabaci, N. spp., and on Amaranthus sp., Commelina benghalensis, C. nudiflora, Lycopersicon esculentum, Ricinus communis, Solanum melongena; also on wound inoculated Buxus sp., Daucus carota, Hedera helix, Ipomoea batatas and Trema amboensis. DISEASE: Black shank of tobacco. GEOGRAPHICAL DISTRIBUTION: Africa (Malawi, Mauritius, Uganda); Asia (Ceylon, China, Formosa, India, Indonesia, Japan, Java, Malaya, Philippines, Sumatra); Central America & West Indies (Cuba, Jamaica, Puerto Rico, Santo Domingo, Trinidad); Europe (Bulgaria, Germany, Greece, Italy, Poland, Romania, U.S.S.R.); North America (U.S.A.); South America (Brazil, Colombia, Venezuela). TRANSMISSION: Soil-borne, persisting in soil for at least 4 years between tobacco crops, and not eliminated by a 3 year rotation or a 4 year fallow (41: 409; 39: 126). Tobacco leaves have been used to indicate disease potential in infested soil after serial dilution with sterile soil (42: 408). Spread in contaminated pond water used in overhead irrigation also suspected (43, 1413). Wind-borne spread up to 800 ft. has been recorded (39: 500).