218 COBN CHOPS 



wingless females produce living young continuously, which 

 in turn at the end of a few days also begin producing young. 

 The lice live on the juices that they suck from the corn 

 roots. Winged females occur occasionally, which estab- 

 lish new colonies. In the fall both winged males and 

 females appear. This last brood lays eggs which live 

 over winter. Ants are often associated with plant lice 

 and it is thought that they assist in protecting them and 

 in caring for the eggs. 



No practical way of restraining the lice has been sug- 

 gested, except that early plowing and clean, thorough 

 preparation of the land will destroy to a large degree 

 those present in the soil. 



The corn ear worm 



The ear worm is the larva of a moth. Two to seven 

 broods are produced each year, depending on latitude, 

 about four broods being the average at the 40th parallel. 

 It is the brood produced at silking time that is most 

 injurious. The worms eat off the grains near the tip of 

 the ear, not onlj^ destroying directly considerable grain, 

 but also opening a way for fungous diseases and ear rot. 



Migratory insects 



Chinch bugs. — While chinch bugs breed in cornfields, 

 the principal damage is due to migrating bugs from adja- 

 cent grainfields after harvest. The migration of wing- 

 less bugs is prevented by barriers, such as a dust mulch 

 10 feet wide, harrowed every day to keep loose, or a plow 

 furrow with post holes every 2 rods where the bugs collect 

 and may be destroyed by kerosene. A barrier of tar is 

 sometimes used. 



