May 5,192.7 
Striped Sod Webworm 
413 
ARTIFICIAI< CONTROL 
Injury to com by the striped sod webworm can more easily be prevented 
than remedied. When a field is in meadow or pasture, the moths aro 
attracted to the low, rich portions where the grass growth is most luxu¬ 
riant. If a sod field be broken and planted to com, injury is most 
likely to occur in such portions. To prevent the injury the sod should 
be plowed as early as possible in the fall, in late July or August if possible. 
Land plowed after the middle of September generally shows little reduc¬ 
tion in infestation compared with that plowed in the spring, because by 
September the majority of the larvae have entered their winter quarters, 
where they are not seriously injured by plowing. If the sod is plowed 
early enough to deplete seriously the food supply of the fall generation 
and force the larvae into winter quarters in an undernourished condition 
and incompletely protected, the method may prove somewhat beneficial. 
Where lands permanently in grass, such as meadows, lawns, and 
parks, are heavily infested, premature drying and browning of the plants 
may be caused, becoming especially evident during periods of drought. 
Little can be done in such cases except to stimulate the growth of the 
grass by applying a quick-acting fertilizer, such as nitrate of soda. 
Fortunately, the portion of a meadow most attractive to this insect is 
the last to suffer from unfavorable moisture conditions and remedial 
treatment in such places will very seldom be required. 
Although poisoned bran bait has been 1 :ested in a few instances, for 
the most part unsuccessfully, no opportunity has as yet presented itself 
to give this method a thorough trial. It may yet be found feasible for 
use in heavily infested grasslands. 
SUMMARY 
• 
Crambus mutabUis is a common species over the eastern half of the 
United States and as far west as Iowa, Utah, and Texas. Its food 
plants seem to be limited to the grass family. 
It has been known to cause injury to young com and to grasslands, but 
in such cases it is usually associated with some other species. 
There are three generations a year in Tennessee, the third being the 
smallest, and gradually diminishing northward until there are only two 
at the northern limits of the species. 
The moths are grass lovers and seek the lower and more luxuriant 
portions of pastures and meadows. They lay about 500 eggs, dropping 
them promiscuously as they fly. 
The larvae in the larger instars are distinctly striped and easily recog¬ 
nized. They construct tubular burrows in the earth opening at the 
surface and feed on near-by grasses, cutting off the leaves and dragging 
them into the burrows. In the fall they construct tubular nests among 
the grass stems, either above or partly in the ground, and pass the winter 
as partly grown larvae, completing* their growth in the spring. 
Crambus mutabilis is more specialized than C. hemiochrellus, its nearest 
relative, and is evidently the terminus of one line of development in the 
genus. 
The larvae seem very susceptible to disease and are also frequently 
parasitized by both Hymenoptera and tachinids. 
Control measures consist of early fall plowing of sod lands intended for corn 
the following year and rotation of pastures and meadows where the insect 
is destructive. Ordinarily natural agencies prevent its injurious increase. 
