30 ANNUAL REPORTS 01 DEPARTMENT OF AGRICULTURE, 1 
Parasite* ol Fruil Insects Exported 
Shipments of natural enemies to foreign coui ither by the 
Bureau directly or in cooperation with State experiment stations, 
comprised several Bpecies oi parasites of the Sai j! -•■ scale to Italy: 
A />/<> linu \ mali I laid., an enei te wooly apple aphid, to M< i 
\ia > ardinalis Muls. to Bolivia for control of t he cottony cushion 
scale; and Trichogramma B ley, a gei i i 1 i L r L r parasite, to 
Australia. 
JAPANESE BEETLES 
DDT Reduces Isolated Beetle Infestation 
A Large-scale experiment in the treatment of a well-established 
isolated infestation of Japanese beetles was carried on at Blowing 
Rock, X. ('.. from L945 to L948. When the work was started, the 
main area of infestation included about 25 of grub-infi 
turf, and scattered light infestations outside this area were found 
later. 
In 1945 DDT was applied to practically all the turf in the main 
area of infestation at tne rate of 250 pounds of 1.0-percent powder to 
th" acre. Trees and shrubs in the area that were susceptible to beetle 
attack were sprayed once with DDT. During the next 2 years some 
of the low-growing shrubbery that was infested was treated with a 
hand duster. 
As measured by the captures of beetles in traps, the treatment save 
marked reductions in infestation. The approximate numbers taken 
in about 500 traps in the treated area \'^r 5 years, beginning in L944, 
the .war before the treatment, were 139,000, 42,000, -J"."" ,23, ). and 
1.6,000. In contrast, the beetles captured in the lightly infested un- 
treated area nearby ed from 357 in 1945 to Li,000 in 1948. 
In the absence of treatment the numbers would undoubtedly have in- 
creased in somewhat the same proportion throughout the entire area. 
This experiment has shown that it is possible to reduce an isolated 
infestation to a very low point. With a more intensive soil-treating 
program and frequent application of DDT against the adult beetles, 
the population could undoubtedly be depressed much further. 
Recommended Soil Treatments Injure Few Plants 
DDT and chlordane do not appear likely to cause noticeable plant 
injury when applied to turf area- or to nur-erv soil at the rate- rec- 
ommended for control of Japanese beetle grubs. Records covering a 
i and at least 10.5 million plants grown in soils t<» which 
25 pounds of DDT per acre had been applied in nurseries throughout 
the East, a- well a- records On I ited turf area-, indicate that 
most plants tolerate this amount <•! DDT. Nearly 1,700 varieti< 
plant-, representing 957 species and ! ra, have not been notice- 
ably affected by Buch :i treatment. Growth of onion; strawberry, 
tomato, lima bean, bush bean, spinach, and spring rye has been retarded 
