30 NEW YORK STATE MUSEUM 



about 9 o'clock in the evening often make flights of 20 or 30 feet 

 at a height of 6 feet or more above the ground and have been 

 observed to make single flights of about one-seventh of a mile. 



The moths lay their eggs in the spring on the under surface of the 

 early leaves in shinglelike oval patches, the average number for 

 the first brood as determined by studies in Massachusetts in 191 9 

 being 386 and for the second brood in 1918, 727. Egg laying begins 

 about 3 1 days after the moths emerge and continues for about 12^ 

 days, though adults may live as long as 30 days. The borer in New 

 York State, at least, displays a marked preference for early planted 

 com and that planted 2 or 3 weeks later than the earliest may escape 

 infestation altogether. 



The young larvae or caterpillars eat out small areas on the leaves 

 and as they increase in size descend and attack the developing tassel, 

 working in the buds and later entering the stem and causing the 

 characteristic breaking or bending at the base. The larger cater- 

 pillars enter the stalk and tunnel through all parts of the plant 

 except the fibrous roots, retarding development and in many cases 

 causing defective fertilization as a result of injury to the tassel. 

 Infested stalks, when the caterpillars are active, are easily recognized 

 by the dry or moist borings near or hanging from circular holes. 



The larvae of the first brood confine their operations largely to 

 tassels and stalks, frequently not injuring the ear. This greatly 

 reduces the possible injury, though corn is planted so early in New 

 York State and the moths appear so late, that it is possible for eggs 

 to be laid directly upon the developing ears. Later developments 

 in the infested areas have shown that there may be serious loss in 

 sections where there is one brood, not only on account of the insect 

 working in the stalks but because of general and somewhat severe 

 damage to the ears. 



The moths of the second brood fly mostly during August and deposit 

 many of their eggs upon the silk of the developing ears, the young 

 borers entering the tip and feeding frequently for some time without 

 marked external evidence of their presence. Later the husks are 

 penetrated, and we have the characteristic signs of borings so fre- 

 quently noted in the com stalks. Feeding may continue until 

 checked by cold weather. The damage is frequently increased by 

 the invasion of various rots and the breaking and decay of the 

 affected parts. The average length of the larval period for the first 

 brood, as established by the Massachusetts investigations, is 44 

 days, the maximum being 57 and the minimum 37 days. The first 

 pupae of the second brood in Massachusetts were foimd in 19 18 on 

 July nth, and were most abundant July 19th to 23d. The pupal 



