64 Stevens— Science of Plant Pathology. [June 



potato bug began its eastern migration. In 1859 it was 

 found east of Omatfa Citv, in 1868 it had reached Illinois, in 

 1870 Ontario, in 1872 New York and in 1874 it was upon the 

 Atlantic seaboard. The potato bug ate ravenously and man 

 was stimulated to new activity in the search for more effec- 

 tive means to overcome insect pests. The use of Paris green 

 and London purple followed as a direct result of this stimu- 

 lus. 



The development of efficient fungicides and insecticides in 

 Europe and America led naturally to the perfection of the 

 machines used in applying these mixtures, and not the least 

 important part played in the development of a practical plant 

 pathology is concerned with the evolution of spraying 

 machines. The first sprayer consisted of a bunch of switches. 

 This was dipped into the spraying mixture which was dis- 

 tributed over the foliage by vigorous shaking. It gave place 

 to an improved spraying broom or brush with hollow handle, 

 the liquid flowing from a reservoir to the brush, from which 

 it was applied to the leaves. Sprayers and pumps followed 

 in turn. Then came the improvement of the nozzle. 



We may recognize two periods in the development of plant 

 pathology: the first or embryonic period extending from pre- 

 historic times to the beginning of the truly scientific investi- 

 gations in the middle of the eighteenth century, and contrib- 

 uting chiefly observations, collections, descriptions; the sec- 

 ond or formative period, during which the foundations of the 

 science were laid, the chief factors of it determined, and the 

 chief lines of future progress marked out. 



It is in no way my purpose to call attention to the part the 

 Carolinas have played in botany as a science, yet I can not 

 refrain in passing from mentioning that prominent place in 

 the history of American mycology is assured to de Schwein- 

 itz, a minister of Salem, N. C, who in 1818 published the 

 first important paper on American fungi; to M. A. Curtis, a 

 tutor in Wilmington, N. C, who in 1830, with Berkeley in 



