CORN PESTS AND DISEASES 



267 



cnanging to the pupa state. The damage done by the 

 second generation consists largely in weakening the 

 stalk so ihat it is readily blown down. Injury by the 

 rirst generation results in serious harm to the crop, 

 preventing the growth of the ears. Upon reaching 

 maturity, the larvae of the second generation do not 

 transform at once, but the majority of them pass the 

 winter as larvae. Early planted com is more apt to 

 be infested than late corn. For instance, corn planted 



Pig 70— The Larger Cornstalk Borer 1 



a, female; i, larva; c, pupa— all somewhat enlarged 



the first and second weeks in April, twenty-five per 

 cent was damaged ; the third and fourth weeks, twenty 

 per cent; May i to 15, fifteen per cent; of that planted 

 May 15 to 31, twelve per cent; June i, eight per cent. 

 In fact, corn planted after June i was practically 

 uninfested. See Fig 88, showing work of the larger 

 cornstalk borer. 



With the more careful and thorough methods of 

 cultivation in the North this insect in all probability 

 will not thrive. Dr L. 0. Howard, entomologist of 



