FARM METHODS FOR THE CONTROL OF INSECTS 35 



plished by burning. The burning over of grass land aids greatly 

 in the control of army worms, chinch-bugs, grasshoppers and 

 plant-lice, while the burning of the stubble will largely control 

 the wheat joint worm. Strawberry beds are sometimes burned 

 over in early spring to destroy the eggs of the root-louse, and 

 aphids on small grains may sometimes be killed out on small 

 areas by covering with straw and burning while the plants are 

 small. 



Plowing. Deep plowing and thorough harrowing are the most 

 effective means of ridding the soil of many pests of staple crops. 



Late Fall Plowing. Where the succession of crops permits, 

 plowing in the late fall is most advantageous, as it destroys the 

 insects while hibernating, although for some insects early fall 

 plowing and thorough harrowing during the fall are preferable. 

 Where plowing is not possible, thorough disking is often used 

 for the same purpose, as on alfalfa. As different insects pass the 

 winter in different stages this method does not affect all alike. 

 Some will be destroyed by having the cells into which they have 

 gone to pass the winter broken up, and being unable to construct 

 new cells they will be subjected to undue freezing and thawing 

 and excessive moisture, and will thus be killed by the weather. 

 Cutworms and the corn stalk-borer pass the winter in the soil 

 as larvae; the cotton boll worm or corn ear-worm hibernates 

 in the pupal stage; while May beetles and click beetles hibernate 

 as newly transformed beetles; but all of them will be similarly 

 affected by the breaking up of their winter cells, which is the 

 most effective manner of combating them. 



Other insects lay their eggs in the ground in the fall and these 

 may be buried too deep for the young to emerge, or larvae or pupae 

 which normally remain near the surface may be turned under so 

 deeply as to destroy them. Thus grasshopper eggs are laid in 

 the fall just beneath the surface, and by plowing in late fall or 

 early spring they may be turned under so that but few are able to 

 emerge, which is the best means of combating them. The apple 

 maggot hibernates in the pupal stage just beneath the surface of 

 the soil, and by deep plowing in early spring the puparia may be 

 buried too deeply for the flies to emerge. 



Young grasshoppers are often destroyed after they hatch by 

 plowing deep furrows, starting at the outside of the field and plow- 



