February, ’24] 
smith: JAPANESE BEETLE 
111 
of various species of Tabinidae and Asilidse destroy large numbers of 
grubs in low marshy situations. In addition, dipterous larvae belonging 
to the family Therevidae, genus Psilocephala, have been found to destroy 
a great many Popillia grubs; in some places the larvae of this species 
were found as numerous as 30 to the square foot. 
Studies have also been conducted for the past year on the various 
bacterial and fungus diseases of the larvae of Popillia in the vicinity of 
Riverton. During the spring of 1923 a mortality of 10 per cent of the 
larvae occurred in some localities, due to what was apparently an 
epidemic of a disease, caused by a species of Coccobacillus. 
In addition to studies of bacteria, investigations are being conducted 
relative to the efficiency of various fungi in destroying Popillia . larvae. 
Under laboratory conditions certain forms, particularly certain Isarias, 
are extremely effective in killing the Popillia larvae. However, under 
field conditions the virulence of the fungus is not so apparent. 
Conclusions 
In the season of 1923 the Japanese beetle increased the area of its 
distribution from 770 square miles to approximately 2500 square miles. 
Owing to the increase in area and cost of inspection of farm produce 
at point of origin, a zone was established to include a large portion of 
the territory in which locally grown produce was consumed. All 
produce shipped to points outside the zone was inspected at the point of 
origin and was then shipped direct to its destination. 
During the past season growers in the heavily infested territory, who 
applied sprays according to directions given by the Japanese beetle 
laboratory, obtained excellent protection of the foliage and fruit on 
apples, grapes and cherries, also of the foliage of shade trees and orna¬ 
mental shrubs. 
Measures of control have been developed whereby the larvae may be 
destroyed in golf courses and lawns as well as where they occur in the soil 
about the roots of various plants. ^ 
In addition various parasitic enemies of the Japanese beetle are 
being imported in large numbers in order to supplement the various 
natural agencies which tend to reduce the numbers of the beetle and to 
serve as a check on the continued increase in concentration of the 
beetles in the areas which have been longest infested. 
The session adjourned at 4:30 p. m. 
