LIBRARY 
I S SI 51 PEST SURVEY BUI 5 hPLANT BOARD 
Vol. 22 Supplement to No. 3 June 10, 1942 
POPULATIONS. AND HOST PREFERENCES OH JUNE BEETLES ( PHTLLOPHAGA SPP.) 
IN SOUTHERN WISCONSIN IN 1941, WITH A SUMMARY OP SIMILAR INFORMATION 
POP THE PERIOD 1935-1941, INCLUSIVE 
By I. B. Chamberlin, C. L. ^luke, Lee Seaton, and J. A. Callenbach l] 
The study of the flights, populations, and host preferences of June 
beetles in southern Wisconsin has been continued since 1934. Accounts of 
the flights of 1935-37, inclusive, of 1938, and of 1940 were given in the 
Insect Pest Survey Bulletin, Supplement to No. 4, Volume. 18; Supplement. to 
No, 3, Volume 19; and Supplement to No. 9, Volume 20, respectively. Methods 
of study, flight habits, and temperature reactions of the beetles are . - 
discussed, in some detail in those reports. r Ahe work- was completed as a. major 
project in 1941; consequently this report includes a .summary of the results 
for the 7-year period, as well as a more detailed account for the year 1941. 
STUDIES IN 1941 
In the 1941 studies eight main groves were used, in addition to a few 
others from which supplementary collections were made. Seven of the 8 groves 
had been used previously. They were located near the following towns or 
villages; Poynette and Leeds, Columbia County; Pipon, Pond du Lac County; 
Dane, Done .County; Lament, Lafayette County; Linden, Iowa County; and Gay s 
Mills, Crawford County. The eighth grove was near Wisconsin Rapids, Wood 
County, The location of these groves, is shown, in figure 1. As formerly, 
the Gay.s Mills area, which was studied more instensively than any of the 
others, is considered separately, whereas the. other areas are grouped. 
Twelve flight observations were made at Gays Mills between April 26 and 
July 1, and 13 in other areas between April. 30 and June 13. All beetles col- 
lected Mere hand-picked from their host plants. 
Numbers and Species of Bee t les Collected 
In the Gays Mills area 12 species of Phyllophaga were taken, which, in 
a decreasing order of abundance, were as follows; Phyllophaga rugosa (Melsh), 
P. fusca (Fr'oel.), B, hirticula (Enoch), P. bal ia (Say), P. ilicis (Enoch), 
P. tristis (P.), P.. prunina Lee., P. implicita Horn, P. marginal is (Lee.), 
P. drake i (Eby.), P. nitjda (Lee.), and P. inversa (Horn). P. rugosa , 
P. fusca , and P. hirticula- comprised 56.64 percent, 28.14 percent, and 7.65 
percent respectively, of the' total beetles taken, and altogether ms.de up 
92,43 percent .of the total. The number of beetles of each species may be 
found in table 1. 
l] Division of Cereal and Porage Insect Investigations of the Bureau of 
Entomology and Plant Quarantine, United States Department of Agriculture, 
and the Wisconsin Agricultural Experiment Station, through its department 
of economic entomology, cooperating. 
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