BUREAU OF ENTOMOLOGY. 313 



corn, ornamental floAvers, and certain shade and forest trees; that 

 it is an active insect and a stron*^ flier, spreading naturally with 

 ease, and is readily carried by artificial means; that in tlie absence of 

 its natural enemies it reproduces in almost incredible numbers; that 

 conditions in the present infested area are ideal for the insect, in con- 

 sequence of wliicJi it lias continued to multiply and spread in spito 

 of restrictive measures practiced. The insect has crossed the Dela- 

 ware River near Riverton, N. J., and occupies on the Pennsylvania 

 side a strip about 7 miles long and from one-half to li miles wide. 

 Its present area of distri})ution is approximately 50 square miles. 



The various phases of the work carried out and under way in co- 

 oj^eration Avith the New Jersey State department of agriculture may 

 be considered under the following divisions: 



Qiiorantine. — A quarantine against the Japanese beetle Avas in- 

 augurated in 1919 and included only sAveet or green corn. Further 

 exptricnce indicated the necessity of extending the quarantine to all 

 other farm crops, as Avell as nursery and greenhouse products, and 

 such a quarantine is established and in successful operation at the 

 present time. As a necessary basis for establishing quarantine areas, 

 Ave have thoroughly scouted the territory to keep track of further 

 spread. Much attention has been giA'en to this scouting work, and the 

 distribution of the beetle from week to week is pretty accurately 

 knoAvn. 



Control. — Increased funds permitted much more effective control 

 operations than previously. To restrict the spread of the beetles at- 

 tempt has been made to maintain a barrier band of dusted or sprayed 

 foliage about a mile Avide completely around the infested area. 

 Within this band all food plants on headlands, along roadAvays. and 

 elscAvhere have been eliminated as thoroughly as possible. Despite 

 effective Avork in keeping the barrier band Avell coated Avith repellents 

 and poisons, indications are that the beetle Avill not be held by it, but 

 Avill continue to spread. 



Within the infested area Ave have encouraged the residents to adopt 

 farm practices to destroy the insect in the grub stage. Systematic 

 collection of beetles by hand has been followed, and great numbers 

 have been destroyed. "Much work has been done to destroy the grubs 

 in the soil by the application of soil insecticides in the Avorst infested 

 ureas. Pleadlands and roadAvays haA-e been kept as clear as possible 

 of food plants by destruction Avitli Aveed-killing chemicals, by fire 

 and otlier means. This Avork is of considerable importance in mini- 

 mizing the chances of distribution of the beetles on passing vehicles, 

 by pedestrians, and otherwise. 



Investigation. — Preliminary insecticide investigations were begun 

 early. During the year just closed this Avork has been materially 

 strengthened and a very large number of materials likely to be re- 

 pellent or poisonous have been experimented Avith. Tests have been 

 made Avith a large series of chemicals likely to prove attractive to the 

 insects, and other lines of inquiry Avere folloAved. In consequence of 

 the quarantine it became desirable to ascertain Avhether plants with 

 earth balled around the roots could be so treated as to destroy any 

 grubs present, and many experiments Avere made. 



Introihiet'wn of nafnral enemicK. — An exi)erienced entomologist is 

 noAV in dapan studying tlie natural enemies of the beetle, and it is 

 24435— AGB 1920 21 



