INSECT PEST SURVEY BULLETIN 
Vol. lg Supplement to Number U June 15, 1938 
POPULATION AND HOST PREFERENCES OF JUNE BEETLES 
IN SOUTHERN WISCONSIN IN 1935, 1936,AND 1937 
By T. R. Chamberlin, C. L, Fluke, Lee Seat on, J. A. Callenbach, 
and P. 0, Ritcher-' 
The following is an account of the distribution, flight, habits, and 
host preferences of species of P^yi i ^pha^a in southern Wisconsin, -'based on 
studies made in 1935, 1936, and 1937. Figure 1 shows the localities in which 
these studies were conducted. In some of the localities more than one grove 
was observed. 
Studies in 1935 
The year 1935 was a year of the flight of the major brood, generally 
known as "brood A." The first beetle was recorded at Madison on April 26, 
before work was begun by the Bureau of Entomology and Plant Quarantine. Fair- 
ly heavy flights had occurred at Gays Mills by May 12. The spring season was 
late and the flight prolonged, and heavy flights occurrod infrequently on warm 
nights. Between May 7 and August 7, U9 flights were observed in lU districts. 
An area was selected in each district which showed, on general examination, 
moderate-to-heavy feeding and the presence of a variety of herbs, shrubs, and 
trees. Groves, largely of bur oaks, showing intense beetle feeding, were 
avoided because of the scarcity of alternative hosts. Each area was observed 
from one to many times, as determined by its availability and its value as a 
collecting ground. Most of the observations were made between 7*30 an< i 11:30 
p.m. Air .and soil temperatures were usually recorded at the beginning of the 
observation period, at the beginning and end of the flights, and at frequent 
intervals during the observation period. 
—'This project is a part of the June beetle investigation being conducted co- 
operatively %y the Division of Cereal and Forage Insect Investigations of the 
Bureau of Entomology and Plant Quarantine, U. S. Department of Agriculture, and 
the Wisconsin Agricultural Experiment Station through its department of economic 
entomology. Ritcher made the flight observations at Gays Mills, Wis., in 1935 
and Callenbach those in 1936 and 1937* Chamber lin, Fluke, and Seaton made the 
observations in the other districts for all 3 years. 
■^/One locality included, Sturgeon Bay, is not in southern Wisconsin. 
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