112 HISTORY OF PHYTOPATHOLOGY 



our growers from the introduction of dangerous patho- 

 genes and pests aroused great antagonism abroad at 

 first as well as some at home. It has, however, resulted 

 in a marked improvement of foreign inspection and in 

 extraordinary activity of our domestic inspection service. 

 The Introduction of Sulfur as a Substitute for Copper 

 in Fungicides. — ^Lime-sulfur has long been known and 

 used as an insecticide and to a very limited extent as a 

 fungicide in cases where disinfection of dormant trees is 

 desirable, as in the case of the peach leaf curl.' Cordley of 

 Oregon in 1906 discovered that much diluted solutions of 

 lime-sulfur might be used with safety and efficiency as a 

 summer spray for apple scab.^ Scott in 1907 devised and 

 tested out the so-called self -boiled lime-sulfur mixture.' 

 He showed that it could be used successfully in the control 

 of the scab and brown rot of peaches, without at the same 

 time causing injury to the tender foliage of the peach, 

 such as results from the use of copper sprays or of solu- 

 tions of calcium sulfids. These discoveries were soon 



' The early history of the use of sulfur solutions for the control of 

 peach leaf curl is set forth in detail by N. B. Pierce in, Peach leaf curl, 

 its nature and treatment, U. S. Dept. Agr. Div. Veg. Path, and Phys. 

 Bui. 20 : 46-66, 1900. Long before this, however, dilute solutions of 

 lime-sulfur concentrate had been recommended as a spray for grapes 

 to control the powdery mildew. (Regel, E. Die Schmarotzergewachse 

 und die mit denselben in Verbindungstehenden Pflanzenkrankheiten, 

 pp. Ill, 112, 1854.) 



'See Cordley, A. B.: Lime-sulfur spray as a preventive of apple 

 scab, Rural New Yorker, March 1, 1908 :202; Oregon Agriculturist, 

 March 1, 1908 : 178, or Better Fruit, September, 1908 : 26; also, Whetzel, 

 H. H., Summer use of concentrated lime-sulfur, N. Y. State Fruit 

 Growers' Assoc. .\nn. Rep., 9 : 31-33, 1910. 



'Scott, W. M.: Self-boiled lime-sulfur mixture as a promising 

 fungicide, U. S. Dept. .\gr. Bu. PI. Ind. Circ. 1 : 1-18, 1908; also, Circ. 

 27 : 1-17, 1909. 



