BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 79 
With one nematode species the pigment produced by the bacterium had 
antibiotic properties. Methods for extracting and purifying it were 
studied. A median infective dose of Coxiella popilliae, n. sp., a 
rickettsia causing blue disease of Japanese beetle larvae, was found to 
be less than 7 cells per grub. Calculations made from the results of 
dosage-infection studies indicated that the doubling time of the 
organism in vivo is about 9 hours. It was also found that development 
of disease in experimentally infected larvae could be prevented by the 
injection of streptomycin or sulfadiazine but not by penicillin or 
aureomycin. 
An improved technique has also been developed for producing milky 
disease spores in mass quantities. By moistening soil-seed mixtures 
with formaldehyde the damping-off of the sprouted seed, used as food 
by the larvae in the process of producing the spores, can be prevented 
or retarded. Optimum effects were obtained with 100 ml. of 0.04- 
percent formaldehyde per kilogram of air-dry soil. No aeration of 
the treated soil was required and the soil treatment did not interfere 
with the infection of larvae or development of the milky disease organ- 
ism. Where severe damping-off was encountered, the formaldehyde 
treatment increased spore yields by as much as 100 percent. Higher 
concentrations of formaldehyde markedly retarded germination of 
the seed and lower concentrations were less effective in preventing 
damping-off. 
Injection Treatment for Balled Nursery Stock Promising 
Preliminary tests have been carried on to develop an injection 
method of eliminating Japanese beetle grubs from balled nursery 
stock to permit movement to uninf ested parts of the country. In these 
experiments, carried on at Moorestown, N. J., ethylene dibromide in- 
jected at the rate of 0.4 gram per square foot of the upper surface of 
the balls was effective in killing third-instar Japanese beetle grubs at 
temperatures from 40° to 70° F. in soil balls from 6 to 16 inches in 
diameter. An injection device has been developed for this work. 
Only 2 out of 48 varieties of plants have thus far shown injury from 
the treatment, 
Japanese Beetle Regulatory Activities 
In cooperation with the States concerned, trap-scouting was done 
during 1952 in every State outside the Japanese beetle-quarantined 
area except Idaho, Nevada, and North Dakota. Collections were made 
in 82 nonregulated localities in six quarantined States. In addition, 
beetles were collected at 24 locations in 5 States bordering the quaran- 
tined area, as well as at 5 places in Illinois and 1 in Missouri. Solitary 
hitchhiking beetles were trapped at the following airfields: Kelly 
Field, San Antonio, Tex.; Maxwell Field, Montgomery, Ala.; and 
Drew Field, Tampa, Fla. Rescouting of Kelly, Maxwell, and Drew 
Fields in June 1953 gave negative results. 
During the summer of 1952, 12,000 airplane flights from 69 infested 
military and commercial airfields in 10 States and the District of Co- 
lumbia were treated with aerosols previous to departure for destina- 
tions in the nonregulated area. In addition, 2,400 residual DDT 
