Abstract
A description is provided for Ustilago syntherismae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Digitaria spp., including D. filiformis, D. ischaemum, D. sanguinalis. DISEASE: Loose smut of Digitaria. Infection sometimes dwarfs the host and causes it to branch more profusely than usual (36, 657); it is also reported that vegetative vigour is much prolonged in infected plants compared with uninfected (30, 432). Surface contamination by the large number of ustilospores when shed may result in some discolouration of the entire inflorescence including sheaths and leaf blades. GEOGRAPHICAL DISTRIBUTION: Africa: 'Congo', Gambia, Kenya, Sierra Leone, South Africa, Sudan, Uganda, Zambia, Zimbabwe; Asia: Azerbaijan, China, Republic of Georgia, India, Japan, Pakistan, Russia (central Asia, far east); Australasia: Australia: NSW (31, 225); Europe: Bulgaria, Czechoslovakia, Denmark (39, 284), Germany, Hungary, Italy, Poland, Portugal, Romania, Russia (European region), Ukraine (52, 354); North America: Canada (Ontario; 46, 3383), Mexico, USA (Alabama, Arkansas, California, Connecticut, Washington DC, Delaware, Florida, Georgia, IA, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maine, MD, ME, Michigan, Montana, Missouri, MS, North Carolina, Nebraska, New Hampshire, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Virginia; 69, 2765); South America: Argentina, Brazil, Uruguay. (33, 634; 40, 209; 48, 2203; 50, 2756; 64, 4163). TRANSMISSION: No detailed studies have been reported; ustilospores are presumably disseminated by air currents and infection is thought to be systemic.