LARGER CORN STALK-BORER. 7 
are darker than the hind wings, and bear faint markings. When 
at rest the wings are held close to the body, forming an acute tri- 
angle. The egg laying is done for the most part either at night or 
in the dusk of evening, the moths flying rapidly from plant to plant. 
The male moth is usually somewhat darker in color than the female 
and always smaller. 
FOOD PLANTS. 
Besides corn and sugar cane, this borer has been reported as feed- 
ing on sorghum, Johnson grass, guinea corn, and grama grass. The 
injury to the four last-mentioned plants is never severe, but in plan- 
ning methods of control they must be considered and an examination 
made to determine whether or not they are harboring the pest. 
NATURAL CHECKS. 
The larger corn stalk-borer has very few natural enemies. A 
‘minute hymenopterous parasite’ has in a very few instances been 
found living in and destroying the eggs. In one case 10 of these 
|minute parasites were reared from two eggs. The larva of a brown 
velvety beetle? sometimes enters the holes in the stalks of stubble 
after the corn is cut and devours the caterpillars found therein. This 
larva has been found to be of great value in reducing the numbers 
lof the borers in fields of sugar cane. The termites or white ants, 
locally known as “wood lice,” have been observed destroying the 
arvee in the stubble in the winter, although apparently only when 
the presence of the larvee interfered with the work of the ants. In 
a few cases bodies of the borers have been found in the stubble killed 
by a fungus, as yet undetermined, which envelops their bodies in 
a white mold. Fungi, however, are too dependent on weather con- 
ditions to be of any practical value in controlling the pest. 
PREVENTIVE MEASURES. 
Rotation is one of the best general preventives of injury from in- 
sects affecting field crops. Experience has shown that where corn 
has followed itself upon the same field for two or more years there 
has been a much greater loss from thé borer than where an annual 
change of crop has been practiced. This is especially noticeable 
where stalks or stubble from the previous year have been allowed to 
remain undisturbed throughout the winter. The moths, upon emer- 
gence in the spring, finding themselves surrounded by the young 
corn, commence egg laying at once, and escape the dangers encoun- 
tered in searching for another field of corn. A forced journey in search 
of young corn results in many of the females being eaten by birds or 
being destroyed because of rain, cold, or failure to find the object of 
their quest. A few moths will always succeed in their search, but the 
1 Trichogramma pretiosa Riley. 
wks 2 Chauliognathus pennsylvanicus De G. 
5 Leucotermes spp. 
