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BULLETIN No. i, SEPTEMBER, 1899. 
THE SUGAR BEET CATERPILLAR. 
BY CLARENCE P. GILLETTE. 
The horde of caterpillars that have been devastating 
the beet fields during the past two weeks, between Palisade 
and Grand Junction, and that have occurred in small num¬ 
bers from Grand Junction west towards Eruita, require the 
prompt attention of all interested in the success of the sugar 
beet culture in the Grand Valley, that the loss to this year’s 
crop may be quickly checked and that severe losses for the 
coming year may be averted. 
During the early part of the week (August 14th to 16 th) 
the writer visited many beet fields in company with Mr. C. 
E. Mitchell and others, for the purpose of determining the 
nature and extent of the injuries, the length of time the at¬ 
tack is likely to continue, what remedies it will be best to 
apply, and other points of importance concerning the cat¬ 
erpillar. 
The insect was found in the fields in all stages of de¬ 
velopment, except the egg. The caterpillars varied in size 
from those that did not exceed a sixteenth of an inch to the 
fully grown individuals that measured from an inch to an 
inch and a fourth in length. A large proportion were half 
grown or more, and many had changed already to the 
chrysalis or pupa state, just beneath the surface of the 
ground. 
The fact that there are still many small worms makes it 
certain that the attack will continue to some extent to near 
the end of the present month (August). A quantity of the 
chrysalids were placed in suitable receptacles, and from 
them several moths, which are the adult insect, have ap¬ 
peared at this writing. The females are found to be heavily 
laden with immature eggs, and it is highly probable that 
within a few days these eggs will be deposited on or about 
the beets for a succeeding brood of worms. It is greatly to 
be hoped that the moths now hatching are only belated in¬ 
dividuals of the second brood and that another full brood 
will not appear this summer. However this may be, not a 
day should be lost in beginning the work of destroying the 
