posed from time to time to take the place of copper, none has 

 been found to so generally meet the requirements as sulfur. 

 Known and used as a fungicide long before the introduction of 

 copper sulphate, it was almost entirely discarded upon the 

 discovery of Bordeaux mixture. With the gradual appreciation 

 of the injurious action of the copper in Bordeaux upon the fruit 

 and foliage of the apple, and its early recognized unsafety on 

 the leaves of stone fruits, came the demand for a safer sub- 

 stitute in the spraying of these fruits. With Cordley's dis- 

 covery of the efficiency and safety of lime-sulfur as a substitute 

 for Bordeaux on apples and Scott's development of the self- 

 boiled lime-sulfur for peaches, the fallacy of a universal fungi- 

 cide was at last definitely recognized. To-day, we accept the 

 fact that both copper and sulfur have a distinct place in plant 

 medicine, and other substances promise to find a place in plant 

 prophylaxis. 



Relation of Fungicides to Insecticides. 



In the development and applications of a fungicide, one of 

 the chief problems which the pathologist has to meet is its 

 combination with insecticides. Modern agricultural practice 

 requires a rigid economy in operation. The cost of labor and 

 the requirements of timeliness in application demand that in 

 most cases fungicide and insecticide shall go on to the crop in 

 the same operation. 



Arsenic in some form continues to be the chief agent in the 

 killing of chewing insects. Nothing has yet proved so effective 

 as nicotine for contact killing of sucking bugs, such as aphis, 

 red bug, psylla and the like. A practical fungicide must there- 

 fore be subject to safe and effective combination with insecti- 

 cides in which both arsenic and nicotine in some form are to 

 be used. Happily, both Bordeaux and lime-sulfur have quali- 

 fied in this respect to a remarkable degree. Wallace has shown 

 that the fungicidal value of lime-sulfur is even increased by 

 combination with arsenate of lead, without any evident decrease 

 in safety to either. Nicotine sulfate, sold under the trade name 

 of Black Leaf 40, has likewise proved a safe and efficient con- 

 tact insecticide in combination with both Bordeaux and lime- 

 sulfur. 



