G9 



CHARACTER OF INJURY TO CORN. 



In young corn still in the bud the larvfB seek out the tender 

 uncurling leaves near the base of the opening portion (see PI. VII, 

 lig. 1). Here they bore through the curled mass, making burrows 

 which show as transverse rows of holes after the leaf has fulh^ opened. 

 Occasionally the plant grows too quickly for the boUworm and the sepa 

 ration of layers by unequal growth may squeeze it to death. As soon 

 as the tassels are beginning to form, and while they are still well sur- 

 rounded by leaves, they are attacked (see PL VII, fig. 2). The larvse 

 now feed on the tassel proper, scarcel}^ ever eating into the leaves or 

 stem. As soon as the ears begin to form the remainder of the plant 

 is no longer disturbed. The damage to corn ears will be considered at 

 greater length elsewhere. 



CHARACTER OF INJURY TO COTTON. 



The method of attack on cotton before the squares have formed is 

 of little importance, since it is very rare for such cotton to be injured 

 by the bollworm. It is interesting, however, as it shows that the 

 spring generation can feed on cotton if forced to do so. Under such 

 conditions they seem to prefer, when small, to bore into the cot3^1edon 

 leaves or buds, and later to feed promiscuously on any part of the 

 leaves. 



The squares are without doubt the part of the plant preferred b}^ 

 the majorit}^ of the larva^. After the newly hatched larvae have gained 

 enough strength to get about readily the}' almost invariably enter a 

 square and begin feeding on it near the base. As a rule the first 

 square attacked is eaten hardly at all, and only a small black puncture is 

 to be seen when the square ''flares" some twent3^-four hours later. The 

 flaring of a square is a very characteristic process, the bracts of the 

 involucre folding back and exposing the inner portion (PI. IX, figs. 

 3 and 4). Almost invariably squares which have flared drop from the 

 plant some hours later, breaking ofi' at the juncture of the petiole and 

 stem. Very rarely the}^ may dry up and remain upon the plant. A 

 very slight injury made by a newh^ hatched bollworm will cause a square 

 to flare, but they can often withstand a considerable needle prick 

 without harmful effects. The second square to be attacked by the 

 growing larva shows a larger scar and generally a trace of excrement 

 and a few silken threads spun by the larva, which has left it before the 

 flaring begins. Such injur}^ to squares is quite generally known as 

 the work of ''sharpshooters;" improperly so, however, since the real 

 sharpshooter belongs to another order of insects. 



After the larva has fed upon two or three squares it may either 

 turn its attention to bolls or continue its depredations on other squares 

 or flowers. It has now increased considerably in size and is about 

 one-third grown. If it continues to feed on squares a large hole is 



