234 



AGRONOMY 



Blights. Blights affect the leaves of plants, often caus- 

 ing them to slirivel as if touched by fire and soon resulting 



in their death. The 

 potato blight may 

 spread through an 

 entire crop and effect 

 its ruin in two or 

 three days. 



Leaf spot. The 

 leaves of plants are 

 frequently attacked 



FIG. 171. Mildew of peaches 

 From Duggar's " Fungous Diseases of Plants " 



by fungi that cause 

 discolored spots in 

 the tissues. Sometimes these are sufficiently numerous to 

 cause the death of the plant or render it unfit for food. 



FIG. 172. Leaf spot on pear 

 From Duggar's " Fungous Diseases of Plants " 



The brown spots that appear on bean pods and other fruits 

 are closely allied to the leaf-spot diseases. 



