CHAPTER VIII 

 ENEMIES OF FARM CROPS 



The chief enemies of farm crops are weeds,- insects, 

 and diseases caused by parasitic plants. A number of the 

 larger animals, such as ground-squirrels, crows and gophers, 

 are sometimes injurious. 



WEEDS 



219. What Is a Weed? A weed is often described as a 

 plant that is not wanted. The worst weed in a corn-field 

 may be corn; that is, if corn is planted too thick, the corn 

 plants crowd each other so that the extra ones may do 

 more harm than is done by common weeds. Johnson grass 

 is a valuable hay plant in the South, but it is so hard to 

 kill that it is a very bad weed. 



220. Value of Weeds. Weeds are a benefit, in that they 

 force men to till the land and often compel crop-rotation. 

 The farmer then secures the many other benefits that 

 come from rotation and tillage. 



But many weeds are of direct value. The best plants 

 in pastures are sometimes those that are weeds elsewhere. 

 One of the great uses of weeds is to renew worn-out soil. 

 In all ages some men have farmed in such a way that the 

 soil has become unproductive. When soil becomes too 

 poor to grow crops, the hardy weeds will still grow on it, 

 and as they decay will gradually build up a productive 



(244) 



