254 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



THE JAPANESE BEETLE. 



The introduction and establishment of this insect in the vicinity of 

 Kiverton, N. J., was mentioned for the first time in the last annual 

 report. The work of eradication and control has been vigorously 

 prosecuted in cooperation with the New Jersey State Department of 

 Agriculture. The operations have been materially enlarged, but in 

 spite of all that has been done the insect is increasing rapidly, spread- 

 ing over new territory, and at the time of the present writing is per- 

 haps 150 per cent more abundant than at the same time last year. 

 Many experimental lines are being worked. Cyanid of soda in solu- 

 tion has been used to destroy the grubs in the ground, at the rate of 

 1 pound to 200 gallons of water and applied at the rate of 22,000 

 gallons per acre. While the beetles are fl.ying. a Avide barrier of 

 poisoned foliage is maintained as completely as possible around the 

 whole area of infestation. Where the beetles are most abundant they 

 have been systematically collected in hand net's. An active collector 

 can secure several quarts of the beetles in a day, and as each quart 

 contains 4,000 individuals, this method is important. About 1,000,000 

 beetles have already been collected. Plowing the soil infested by the 

 grubs and pupae appears to destroy them. It will be necessary to do 

 this kind of work very extensively in waste places and many areas not 

 under cultivation. Weeds along the roadsides have been burned to 

 destroy their food and render such places unattractive to the beetles, 

 thus reducing the danger of their being carried by vehicles, pedes- 

 trians, and so on. In the same wa}^, waste places along ditches and 

 other spots which can not well be treated with cyanid are being cleared 

 of Aveeds, and this work is being extended into the wide barrier of 

 poisoned foliage surrounding the area of infestation. Close study is 

 being made of the relative abundance of the insect in different parts 

 of the area and on the methods of dissemination, and a quarantine is 

 in force providing for the examination and certification of green 

 sweet corn going out to market, since the beetles penetrate the tips of 

 the ears and could thus be widely spread. A local citizens' committee 

 has been established, which is of greatest assistance in the work of 

 arranging cooperation of property holders with the agents of the 

 bureau and the State. The work is now Avell organized, and we have 

 a much better idea of the problem. It seems, from the rapid increase 

 and spread of the insect during the summer of 1919, that the work 

 must be greatly enlarged to be entirely successful. 



INSECTICIDE INVESTIGATIONS. 



At the various field laboratories tests have been made of many 

 proprietary insecticides in comparison with homemade articles. 



Work on the so-called " Derris," an insecticide made from plants 

 of the genus of this name, has been completed. If this insecticide 

 can be obtained in sufficient quantities it will prove an important 

 addition to our list of substances that kill soft-bodied insects like 

 plant-lice. 



Studies of the various arsenical insecticides, like arsenate of lead, 

 arsenate of lime, zinc arsenite, and so on, have been continued. Large- 

 scale feeding experiments have been carried on with caterpillars 

 and other insects. Experiments under different climatic conditions 

 with these substances have also been continued. Additional expe- 



