Diseases of Plants 



303 



/i. F. PooZe, AT. J. -Ezp*. 5a. 



FIG. 171. Bean seeds showing anthracnose spots. If these seeds are planted, 

 the disease will be transmitted to the plants of the next crop, 

 u 



swellings when they are 

 destroy them by burning. 



green " and immature, and 



BEAN ANTHRACNOSE 



The most common and perhaps the most destructive of 

 the diseases that attack varieties of the common or kid- 

 ney bean is the disease known as bean anthracnose. It is 

 nearly always present on some varieties. The fungus at- 

 tacks pods, stems, leaves, and even roots, causing dis- 

 colored blotches to appear. On the pods these first appear 

 as small, dark-colored spots which soon increase in size, be- 

 coming quite conspicuous. They are usually somewhat 

 circular and black or rusty, but may be pinkish at certain 

 stages. These " cankers," as they are called, become 

 sunken and dry and hard. It is in these areas that the 

 fungus is living. Spores are produced on the surface of 

 the canker ; and as these are sticky when wet, they are 



