8 
BULLETIN 94 . 
About the first of May reports began to come in of extensive 
injuries to sugar beets from cutworms. As near as could be deter¬ 
mined not less than four or five hundred acres of beet land in 
Northern Colorado had to be re-seeded this year because of the rav¬ 
ages of cutworms. Next to virgin soil, the fields that were in 
grain the previous season seem to have suffered most and barley 
seems to have been the grain that attracted the moths for the dep¬ 
osition of their eggs far more than anv of the others. 
On May 29, in company with Mr. H. H. Griffin, one of the 
field agents for the Fort Collins Sugar Company, I visited Mr. John 
Hice’s farm near Fort Collins. He partially plowed a field of bar¬ 
ley stubble late last fall and then finished plowing in the spring 
and put the field in to beets. The beets on the fall-plowing were 
in very good condition, but upon the spring plowing they were so 
badly taken by the worms that it was decided to re-plow the entire 
field and seed again. At that date, May 20, the worms were fast 
disappearing and many pupae could be found and fields seeded af¬ 
ter this date were not seriously attacked by the worms. The 
spring was unusually late this year so that it is probable that in 
an ordinary season the cutworms would do little injury to beets 
after the 10th or 15th of May, or after the moths begin to appear 
upon the windows or about the lights of our houses. May 20th 
was the first date we noticed them upon our windows the past 
summer. 
On May 30, Mr. S. A. Johnson went to Aurora, a suburb of 
Denver, to investigate cutworm injuries and was aided in the work 
by Mr. H. Rauchfuss, who had written the Station concerning the 
injuries by the worms. Mr. Johnson found the worms mostly full 
fed or in the pupa state. The worms were pupating about two 
inches beneath the surface in vertical burrows with the head of 
the chrysalis towards the mouth of the burrow. The earthen 
cells at the bottom of the burrow were quite firm though they could 
be crushed without difficulty between the thumb and fingers. A 
quantity of the worms were brought into the laboratory and placed 
in breeding cages for the purpose of rearing the moths and it was 
found that nearly half of the worms were parasitized. The ma¬ 
jority of the parasitized individuals seemed to be entirely eaten out 
beneath the skin and to be packed full of minute pupae of a species 
of CopecLosoma. In one instance 1705 of the adults issued from a 
single worm. See Plate I. Fig. D. Two Ichneumon parasites 
(Ichneumon Iono-n /us and Amblyteles subrufus ) were also bred 
from the worms. 
Two pupae and worms brought into the laboratory the last of 
April began appearing as moths June 26. 
Plowing during the summer or fall and keeping the ground 
clean of all vegetation until winter will give almost perfect pro- 
