BUREAU OF ENTOMOLOGY. 383 



An extensive study of the feeding habits of the Japanese beetle 

 has been carried on for several seasons and data brought together 

 in a paper on Feeding Habits of the Japanese Beetle which Influence 

 its Control, published as Department Bulletin 1154. 



Extensive experiments have been made in replacing the soil ball 

 of coniferous nursery stock with an artificially made ball free from 

 grub infestation to permit the movement of such stock by nursery- 

 men from the infested area. A fair proportion of plants thus 

 handled have come through the second season after such treatment 

 quite satisfactorily, and it is believed that this method gives promise 

 for the use of nurserymen interested in the movement of such stock. 



Much attention has been given to the investigation of insecticides 

 for the destruction of the beetles and to kill the grubs in the soil. 

 A fair killing of the beetles was secured from the use of arsenate 

 of lead at the rate of 4 pounds to 50 gallons of water with 2 pounds 

 of flour or casein spreader. One or two applications in most cases 

 were sufficient when applied thoroughly to protect the foliage dur- 

 ing the beetle season. Further experiments have pointed out certain 

 improvements in arsenical sprays, which, however, must be subjected 

 to further investigation before definite conclusions are warranted. 

 Many materials have been tried in the hope of finding a substitute 

 for arsenicals for use against the beetle without, however, very much 

 success thus far. Large-scale spraying work has been done in or- 

 chards during the beetle season to ascertain the degree of protection 

 from attack which follows different spraying practices. The results 

 show that orchardists can protect their trees and fruit from the 

 beetle by thorough and timely applications of arsenate of lead. Sub- 

 stantial progress has been made in perfecting methods of treatment 

 of infested outdoor-grown nursery stock for the destruction of grubs 

 which may be in the soil around the roots. Wliile no one treatment 

 of universal application has been worked out, several have been 

 developed which are of value under varying conditions. 



Methods for the treatment of soil in which infested or noninfested 

 nursery stock may be heeled in have been investigated. Arsenate of 

 lead worked thoroughly into the soil has given rather satisfactory re- 

 sults. Further work, however, must be done before this method is 

 recommended, especially to determine the tolerance of different 

 plants to soil treated with arsenate of lead. The destruction of grubs 

 in infested grass lands, such as golf greens and fairways, can be ac- 

 complished, it has been found, by the use of carbon disulphid emul- 

 sion. In this way the grub population in sod land can be reduced 

 at a reasonable cost from 60 to 75 per cent. 



Grape insects. — Investigations of grape insects in cooperation 

 with the Ohio Agricultural Experiment Station, with headquarters 

 at Sandusky, Ohio, have been continued, special attention being given 

 to the three-banded grape leafhopper, Erythroneura tricincta^ variety 

 cyrabium^ which seems to be the predominating injurious form in 

 that region. These insects are increasing greatly in abundance, with 

 corresponding injury to vineyards. Careful biologic studies of this 

 and related species are under way, and a preliminary manuscript on 

 the three-banded form has been prepared. Experiments in the con- 

 trol of leafhoppers on grape have been directed toward improving 



