Abstract
A description is provided for Leveillula taurica. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Gossypium barbadense, G. hirsutum and Cyamopsis psoraloides[Cyamopsis tetragonoloba]. Also on many other trees and shrubs belonging to the Leguminoseae, Malvaceae and Euphorbiaceae (Salmon, 1900; Blumer, 1933; Tarr, 1955; 37: 521). DISEASES: Powdery mildew of cotton and guar. The host becomes completely covered with the fungus which mostly forms conidia and rarely cleistothecia. Severe attacks cause defoliation. Komarov (1895) reported that in Seravschan-Turkestan every plant of the steppes up to 1219-1524 m is attacked. The fungus does not occur beyond 1829 m. GEOGRAPHICAL DISTRIBUTION: World wide but mainly in the mediterranean region, Central Europe and the Near East (Dennis, 1960; CMI Map 217; 37: 400). TRANSMISSION: Wind borne. In the Sudan the pathogen over-summers on Euphorbia heterophylla, a common weed (37: 521).