6 



cultural teaching and practice. They rapidly took from the 

 horticulturist those functions and problems to which their pro- 

 fessional training and obligations justly entitled them. The 

 process of transferring the plant disease and insect pest work, 

 especially their practical applications, from the horticulturist 

 to the plant pathologist and entomologist is still going on. 

 Another decade will see it completed. This division of labor 

 and differentiation or specialization has had its usual reward 

 in a phenomenal progress in disease and pest control. America, 

 to-day, is twenty-five years in advance of Europe in the science 

 and practice of plant disease control. The day of the profes- 

 sional plant doctor is at hand. Already the progressive farmers 

 and fruit growers are bidding against the agricultural institu- 

 tion of the country for the services of the professional plant 

 pathologists. They are buying their services with their own 

 hard cash, and the institutions must look to their salaries if 

 they expect to retain for State and Federal service the best 

 men in the profession. 



What constitutes a Good Fungicide. 



A fungicide is a substance which properly and timely applied 

 to susceptible parts of the living plant will protect it from the 

 attacks of pathogenic organisms. 



The requirements of a good fungicide are effectiveness against 

 the pathogene to be controlled, safety to the plant to which 

 applied and adhesiveness. As corollaries to these fundamental 

 requirements are to be noted cheapness, ease of application, 

 and miscibility with insecticides. 



With the introduction and development of Bordeaux mixture, 

 copper became the all but universal active agent in fungicides. 

 Bordeaux meets the above requirements of an acceptable 

 fungicide to a remarkable degree. Copper is probably the most 

 active fungicidal agent yet discovered. Combined with calcium 

 in the form of a colloid known as Bordeaux mixture, it pos- 

 sesses a degree of adhesiveness as yet unsurpassed. Its inju- 

 rious action on the living tissues of many plants, especially 

 apples, peaches, plums and cherries, has led, however, to a 

 persistent search for substitutes. Among the substances pro- 



