36 
'"''Bach firing^'' a somewhat old-fashioned practice, is of great use in 
destro^'ing army worms, cutworms, and otlier forms of insects when 
the}^ occur in such nmnbers as to ruin a crop. It consists in burning 
a rather wide stretch in advance of the wind at the farthest extremity 
of the iield, and then stamping this out to prevent the fire from reach- 
ing other fields beyond. The field is then burned, beginning with the 
side from which the wind is blowing. This has the efiect of destroying 
the entire field, with all the cutworms and many other insects which 
it contains, with practically no danger of the fire spreading to fields 
where it is not desired. 
When cutworms assume the habit of traveling in armies they should 
be treated in the same manner as advised against the army worms. 
ARMY WORMS. 
In addition to the army cutworm that has been mentioned and the 
variegated and spotted cutworms, which sometimes exhibit the same 
migratory tendency', there are three important species of beet-feeding 
caterpillars, allied to the cutworms, but lacking the true cutworm 
habit. The most important of these is the beet army worm. 
THE BEET ARMY WORM. 
In the year 1899 this species, which had not previously attracted 
attention by its ravages, became prominent as an enemy to the sugar 
beet in Colorado. Subsequent study showed that it had been observed 
at an earlier date attacking crop and other plants in New Mexico and 
in California. It is an imported pest, and, although not at the present 
time of great importance, bids fair, in course of time, to become a 
serious enem}" to the cultivation of sugar beet in America. It has 
evidenth^ come by wa}^ of California and is traveling eastward, a 
method of migration of which there is precedent in the Colorado 
potato' beetle. 
The moth (fig. 32, a) is mottled gray, resembling the plain form of 
the related fall army worm. The fore-wings are broader and paler, 
and the reniform and other markings are more distinct. The wing 
expanse is less than an inch and one-half. The larva is rather slender, 
with a small head, and the body greenish or olivaceous and striped as 
shown (fig. 32, J, c, and fig. 33). 
When migrating, the beet army worm attacks several forms of veg- 
etation. Sugar beet appears to be the favorite host plant; table beets 
are also relished, and it feeds quite as well on lambsquarters. pigweed, 
and saltbush (Atriplex). When numerous, corn, potato, pea, onion, 
sunflower, and the leaves of apple, mallow, Xleotkina gJauccu Cleome, 
plantain, and wild grasses are eaten. In southern California the moths 
appear in April and until June; caterpillars of the first generation 
