The first report of gray leaf spot (GLS) of maize, caused by Ce/cospora zeae
mayd/s Tehon and Daniels, dates back to 1924 when the disease was observed in
Alexander County, southern Illinois. By 1943, the disease was observed
causing extensive leaf blighting in Tennessee and Kentucky, reaching severities as i high as 94%. In 1949, the disease was observed in Blacksburg, Virginia with
repeated and more severe occurrence in 1950. During the summer of 1962,
Kingsland reported that the occurrence of gray leaf spot was restricted to the
Blue Ridge mountain area in the western comer of South Carolina. The occurrence
of the disease in that area was attributed to the existence of a specific set of
microclimatic conditions. The author also speculated on the possible existence of new pathogenic biotype of the fungus in that area.