164 
IOWA ACADEMY OF SCIENCE You XXIX, 1922 
and is the one which has caused most of the damage during the 
past fifteen years or more. 
As early as the summer of 1909, brood A in numbers sufficient 
to do serious injury was spread over a large area in southern 
Wisconsin, northern Illinois, northeastern Iowa and a small 
corner of southeastern Minnesota. The grubs have reappeared 
in this territory in the summers of 1912, 1915, 1918 and 1921. 
In 1921 the area of damage in Iowa was much enlarged over 
that of previous years, and southeastern Iowa came in for a 
heavy share of the loss. Twelve counties untouched in a serious 
way in 1918 were invaded. The accompanying map shows in a 
comparative way the infested regions of 1918 and 1921. These 
data were secured through personal visits to infested regions 
and by correspondence with the County Agricultural Agents. 
Mr. Fred D. Butcher, Extension Entomologist, gave valuable 
information also. 
In many parts of the newly infested area the injury was severe. 
Reports of losses range from 15 per cent of the crop to a total 
loss in some fields. Corn and potatoes suffered heavily but blue 
grass pastures seemed to be most seriously damaged. In many 
pastures the grubs were so abundant as to entirely cut loose the 
roots until the sod could be rolled up like a rug. 
From Lee county came the report of grubs as thick as “75 to 
150 per square foot” with a 30 to 50 per cent loss of corn and a 
70 per cent loss of blue grass in some fields. Many large counts 
of grubs were made though no other reports showed as many 
grubs to a given area as this. Twenty- seven grubs were found 
in a post hole left open for two hours, while in a corn field twen- 
ty-two grubs were found in two hills. 
The adult May beetles of this brood will appear in the spring 
of 1923 and it is planned to make a study of them to determine 
the number of species involved and their relative importance. 
Biology Department, 
Iowa Wesleyan College. 
University of Illinois Agricultural Experiment Station Bulletin No. 186. 
