28 Farmers’ Bulletin 1294. 
fore, recommended that any questionable insects found boring in 
corn be sent to the nearest agricultural experiment station, or to the 
Bureau of Entomology, for identification. 
THE CORN EARWORM.?* 
On account of the similarity of its damage to the ears of corn, 
the corn earworm (Fig. 22) is very often mistaken for the corn 
borer. This insect is also known as the cotton bollworm, tomato 
fruitworm, and tobacco budworm. 
The corn earworm, however, is not a true boring insect and usually 
confines. its damage to the silk and kernels of the ear, whereas the 
corn borer habitually feeds not only upon the silk and kernels of the 
ear, but also bores into the cob. Unlike the corn borer, the corn 
earworm does not bore into the stalks, although if the ears have not 
developed on young 
plants it often feeds 
upon the leaves and in 
the growing tip or 
“bud” of the plant. 
This injury sometimes 
results in broken-over 
tassels which at a dis- 
tance resemble corn- 
borer damage, but close 
examination will show 
that these tassel stems 
have not been tunneled. 
This characteristic 
Fic, 22.—Three corn earworm larvze, seen from the side, SCrVES to distinguish 
showing color types : Upper darva, green ; middle one, such injury from that 
rose colored; lower one, dark brown. Not quite twice ‘ 
natural size. (Quaintance and Brues.) Of sthe corn borer. 
During the late fall, 
winter, and early spring the corn earworm is never present in the ears 
of corn or in the stalks, whereas the corn borer may commonly be 
found in ears and stalks of corn at this time in areas where the insect 
is numerous. 
The caterpillars of the corn earworm are about 13 inches long 
when full grown and very variable in color, ranging from tints of 
green, pink, rose, yellow, and brown to almost black. They may be 
beautifully striped, or spotted, with brown, black, or yellow along 
the side and back, or they may be entirely free of stripes or spots. 
In appearance they can be readily distinguished from the corn borer 
by the fact that they are nearly twice the size of the latter. The 
hairs arising from the d/ack tubercles, or warts, on the back of the 
earworm are much longer and stouter than those arising from the 
brown tubercles on the back of the corn borer. The castings of the 
earworm are coarse, wet, and foul, while those of the corn borer are 
more finely divided and usually dry. This insect is widely distributed 
throughout the corn region of the country and did infinitely more 
damage in 1921 than the corn borer. 
23 Heliothis obsoleta Fab. 
