176 INSECTS AFFECTING VEGETATION 



specimens have some white spots on the disks of the wings. The 

 moth is nocturnal, and has been taken by us flying about electric 

 lights, and also at sugar. The eggs have not as yet been found. 



There is but one brood in a year, and by the end of June the 

 caterpillars are over half grown, and have mostly left the grasses in 

 which they made their start and entered the thicker-stemmed plants, 

 of course including corn. 



Fortunately, injuries by this insect are not of a kind to require 

 special measures of prevention or remedy. It is, of course, impos- 

 sible to poison the larva in the corn-field, and the breeding habits 

 of the insect are not such as to enable us to destroy it in the pupa 

 state by any ordinary operation. If headlands and other grassy 

 lots adjoining corn show in early spring an unusual abundance of 

 these insects, it might be -worth while to mow the infested turf and 

 carry away and feed the cut grass promptly, before the caterpillars 

 coulci escape to enter the corn. (Bui. 95 111. Agr. Exp. Sta.) 



Larger Corn Stalk-Borer.* In many southern cornfields a heavy 

 wind late in the season, before the corn is matured, does great dam- 

 age by breaking the plants off at the surface of the ground, thus ruin- 

 ing them. An examination of these broken stems will, in most cases, 

 show that they have been greatly weakened by the burrows of a larva 

 or caterpillar. This larva is known as the larger corn stalk-borer. 

 Its work is largely within the stem of the plant and is so concealed 

 that, in most cases, unless weather conditions make it conspicuous, 

 the presence of the insect passes unnoticed. (Cir. 116, B. of E., U. S. 

 Dept. of Agr.) 



This insect seems to have been originally an enemy of sugarcane 

 and to have first transferred its attention to corn in the southern part 

 of this country, where corn and cane are grown over the same terri- 

 tory. In the United States this borer is found almost universally 

 throughout the South, from Maryland to Louisiana and westward to 

 Kansas. 



Corn is damaged by these caterpillars in two ways. First, in 

 the early part of the season, while the plants are small, they work 

 in the throat of the young corn, and if the tender growing tip within 

 the protecting leaves is once damaged all chances that the plant will 

 become a normal production specimen are gone. In many sections 

 of the South this is commonly known as bud-worm injury, and 

 though there are several other insects which cause a similar mutila- 

 tion of the leaf, a very large proportion of the so-called bud-worm 

 damage may be charged to this insect. The effect of its work on 

 the leaves of the young corn plants is similar to that resulting from 

 attacks by the corn billbugs and is evidenced by the familiar rows 

 of small circular or irregular holes across the blades of the plant. 



The other form of serious damage chargeable to this pest occurs 

 later in the season. The larvae, having then left the leaves and de- 

 scended to the lower part of the stalk, tunnel in the pith. If the 

 larvae are at all numerous in the stalk, their burrows so weaken the 

 plant that any unusual strain will lay it low and destroy all chance 

 of its maturing. 



See page 609, for illustration. 



