Downy mildew (Sclerospora graminicola) on Everglade Millet in Florida.

Among the downy mildews or Peronosporaceae, the genus Sclerospora has attracted increasing attention on account of its destructive parasitism of various valuable gramineous crops. Of this genus, the species SolerosfOTCk grammicola (Sacc.) Schroet. is the most widely distributed, occurring in northern temperate portions of the United States and Europe and in both temperate and tropical regions of Asia, and causing in the aggregate considerable injury to millet and related crops. Yet the present knowledge of this fungus in many respecta is scanty, and additional information as to its occurrence in new localities or on additional hosts, its severity, persistence, and spread under different conditions, is necessarily of interest from both the agricultural and mycologie points of view. Therefore, when this species, for the first time in this State and on this hostj was found by the junior writer in November, 1922, on Everglade millet at Vero Beach, Fla., and when during the following year it was encountered also in other widely separated parts of the State, it seemed important to investigate the destructive activity of the parasite on this new host under subtropical conditions and to appraise the possibility of its becoming a menace to Florida's agriculture. The results of this investigation are presented in the following paper.