METHODS OF STUDYIN^G rUl!^GI 11 



atmosphere never directly causes a fungous disease. 

 Sucli diseases, as already indicated, are produced by 

 minute plants, which never arise spontaneously, but 

 always from some spore, or other reproductive form of a 

 previously existing plant of the same species. But 

 weather conditions may be favorable to the rapid devel- 

 opment of these fungi, and so indirectly cause the 

 diseases. 



METHODS OF STUDYING EU^STGI 



The successful study of the minute characteristics 

 of most fungous diseases requires the use of a compound 

 microscope. These, however, can be obtained for a 

 comparatively small amount, and will well repay the 

 investment in the w^onders revealed. By the aid of some 

 such little book as Phin's ^^How to Use the Microscope," 

 or Bausch's ^'^ Manipulation of the Microscope," almost 

 anyone can learn how to manipulate a microscope, and 

 can examine the microscopic characters of the various 

 fungi affecting crops. One desiring to undertake such 

 study would find the following books helpful : 



Bennett & Murray : Cryptogamic Botany. 



Burrill : Parasitic Funsri of Illinois. 



Plowright : British Uredinia? and XJstilaginige. 



Scribner : Fungous Diseases of the Grape and Other 

 Plants. 



Smith : Diseases of Field and Garden Crops. 



Ward : Diseases of Plants. 



The bulletins of the United States Department of 

 Agriculture, especially the Journal of Mycologij, and of 

 the various experiment stations, v/ill also prove very 

 useful. 



METHODS OF DISTRIBUTIO.N 



There are many ways in which fungous diseases are 

 distributed, although the commonest one is by means of 



