BUREAU OF ENTOMOLOGY. 237 



THE JAPANESE BEETLE (POPILLIA JAPONICA). 



The recent introduction in the vicinity of Eiverton, N. J., of the 

 Japanese beetle {PopiUia japonica), a serious insect pest in Japan, 

 has resulted in an investigation of the insect by the Bureau of Ento- 

 mology and an attempt at its eradication in cooperation with the 

 New Jersey State entomologist. A laboratory for biological and 

 other studies has been established at Eiverton, and this place has 

 been made headquarters for the eradication work. 



It appears that the beetle was brought into this country in ship- 

 ments of Japanese iris during the sunmicr of 1911, probabl}' in the 

 egg or larva stage in the soil about the rhizomes of the iris plants. 

 Some 625 acres are now heavily infested Avith the beetle, and it is 

 scatteringly found over some 7,000 to 10,000 acres, with outh^ing in- 

 festations over not less than 25,000 acres. 



The insect has been found to be a very general feeder, attacking 

 grape, apple, cherry, buckwheat, sweet potato, corn, and many o-na- 

 mentals and weeds, as smartweed, morning-glory, black locust, iron- 

 weed, etc. It has been recorded from a total of 41 plants. 



The immature stages are passed in the soil, where the larvae feed 

 on decaying vegetable matter. The adults appear by midsummer, 

 continuing until cool weather in fall. During hot days the beetles 

 are strong fliers, which adds much to the danger of their spread. 

 The insects attack the ends of ears of sweet corn, and in the movement 

 of green corn to market can be scattered to various parts. 



In the work of eradication several lines are followed, as the treat- 

 ment of infested soil with sodium cjanid solution, the destruction 

 of breeding grounds by plowing, and keeping the insects away from 

 roadsides by the use of kerosene oil and other means. Direct meas- 

 ures against the beetles are taken by applying poisons as nearl}' as 

 possible to the entire infested area, working from the periphery of 

 the area inward. A large amount of hand picking is also being done 

 and great quantities of the beetles have already been collected and 

 destroyed. 



CEREAL AND FORAGE INSECT INVESTIGATIONS. 



Mr. W. R. Walton has continued in charge of this important section 

 of the work of the bureau. 



European corx borer. — Doubtless the most important development 

 of the year with respect to insects affecting cereal crops was the 

 discovery, late in the summer of 1917, that a very serious European 

 pest of Indian corn had become established in eastern Massachusetts. 

 This lepidopterous insect (Pyrausta nuhilalis) is well known in 

 Europe and Asia, where it occurs in injurious abundance throughout 

 central and southern Europe and west central and northern Asia atid 

 Japan. 



Among the cultivated crops attacked in these countries are corn, 

 hemp, hops, millet, several wild grasses, and many common weeds. 

 In this country corn is the principal cultivated crop seriously injured, 

 but the damage to that crop is so serious as to cause the gravest appre- 

 hensions should this insect spread into the great corn belt of the 

 Middle West. The caterpillars, of which there are at least two 

 generations 'annually, bore into the stalk, ear, and tassel of the plant. 



