FARM METHODS FOR THE CONTROL OF INSECTS 



37 



the case, it will usually be preferred to them as far as it is 

 available. 



Clean Farming. After a crop has been harvested there is 

 usually some portion of the plant which is allowed to remain 

 on the land. In this refuse the insects peculiar to the crop often 

 feed and multiply until killing frost and then hibernate over 

 winter, ensuring injury to similar crops on the same land the 



FIG. 25. A field of cabbage stumps in midwinter, affording ideal condi- 

 tions for the hibernation of cabbage pests. 



next year. Thus the wheat joint worm and the corn stalk-borer 

 both winter in the stubble of those crops, and the chinch-bug 

 commonly hibernates in the butts of corn stalks, all of which 

 may be largely controlled by burning the stubble. Possibly 

 the most important means of control of the cotton boll weevil 

 is the destruction of the stalks in the fall as soon as the cotton 

 can be picked, thus preventing the weevils feeding and starving 

 them out before they are ready to hibernate, and removing the 

 shelter for hibernation. Thus all the remnants of a crop such as 



