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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
grubs to one square yard. As far as is known, the insect has confined its 
spread to an outward movement of five to fifteen miles yearly from the 
original territory. No new infestations are known to occur at any con¬ 
siderable distance from the area covered by the main infestation. 
The losses caused by the attacks of the Japanese beetle and its larvae 
on economic plants were greater in the aggregate in 1923 than during 
any previous season. The injuries to sod in lawns, golf courses and 
pastures, have been increasingly severe as the grubs have become more 
numerous. The damage to shade trees and fruit resulting from the 
attacks of the beetle was, in some localities, greater than occurred in any 
previous season. However, in the vicinity of Riverton, N. J., where 
fruit and shade trees were properly sprayed, excellent protection to the 
foliage was obtained. 
Prevention of Spread by Quarantine Measures 
Since the inception of quarantine regulations against the Japanese 
beetle in 1919, regulations provided in Federal quarantines as well as 
quarantines promulgated by the States of Pennsylvania and New 
Jersey, have been enforced. This has included the inspection of farm 
produce, particularly green or sweet corn, cabbage, lettuce and grapes, as 
well as the inspection and certification of soil, compost, manure and 
general nursery, ornamental and greenhouse stock. Until the summer of 
1923 all restricted produce was inspected at the point where it originated, 
or on the farm where grown. Owing to the large size of the infested 
area in 1923, the greater cost of inspection at point of origin and also to 
the fact that the City of Philadelphia then came within the infested 
area, the method of carrying out the farm products quarantine was 
changed from one of inspection at the farm or point of origin, to a 
zone system on the following general plan. Taking the Philadelphia 
market district as a center, a zone was established with a radius of 
approximately 25 miles. Fully 90 per cent of the restricted farm pro¬ 
duce originating within the beetle infested territory and coming to the 
Philadelphia market is consumed within the area included in this zone. 
All produce originating within the infested area and consigned to the 
Philadelphia market was allowed unrestricted movement within this 
zone. It was recognized that farm produce moving from the infested 
area to more distant points, as for example New York, Atlantic City, 
Allentown and Wilkes-Barre should be inspected, but since this could 
not be done in the market, it was inspected and certified at point of 
origin and shipped direct to its destination. By provisions of the State 
