30G ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



fluctuations of the insect and the injury caused by it in its original 

 homes in the hope that this I^nowledge may Ije helpful to us. In 

 Japan a survey was made of the region eas^ih^ reached from Yoko- 

 hama, and investigations were also made in the vicinity of Sapporo 

 on the island of Yezzo. So few gipsy moth were found in the latter 

 region that it seemed best to confine the greater part of the work to 

 the territory near Yokohama, where several fair-sized infestations 

 were available. Biological studies were taken up at this point and 

 several shipments of parasites have been forwarded to the gips}"" 

 moth laboratory in Massachusetts. Owing to failure to have these 

 shipments properly iced throughout the entire trip, they arrived in 

 poor condition. 



The European investigations consisted of a survey of conditions 

 of gipsy-moth infestation in France. Italy, Spain, and Germany. 

 The infestation in German}^ this year is practically negligible, and 

 the same is true of Austria and Poland, the latter country having 

 been visited in the hope of securing natural enemies of the gipsy 

 moth. Very little parasitic material has been received from Europe 

 this year as a result of this investigation, but data concerning con- 

 ditions have been secured and considerable work that is of particular 

 value in the parasite investigations has been clone in the museum at 

 Berlin and elsewhere. 



The parasites and natural enemies of the gipsy moth and brown- 

 tail moth that have already become established in New England have 

 been found in large numbers in some localities. The great difficulty 

 appears to be that all the different species concerned are not abun- 

 dant enough over a wide area so that a reasonable measure of control 

 results. Colonization work was continued and areas in all the in- 

 fested States received plantings of parasites that did not occur there 

 heretofore. There still remains a considerable amount of this work 

 to be done before all of these beneficial species are liberated through- 

 out the infested area. 



The temperature during the winter was extremely low in manv 

 sections of New England. On this account an enormous number of 

 gipsy-moth egg clusters failed to hatch. This has resulted in a de- 

 creased amount of defoliation from that of the previous year, par- 

 ticularly in localities where the egg clusters were laid high on the 

 trees and were not protected during the winter by snow or ice. 

 Considerable defoliation by the gipsy moth has been observed in New 

 Hampshire, south of Lake Winnepesaukee, and in the southwestern 

 section of Maine. In parts of this region the trees were denuded 

 over large areas. In many of these localities the wilt disease de- 

 stroyed many of the larvoe and parasites were abundant. There has 

 been less defoliation in Massachusetts and Rhode Island than during 

 the previous year. 



CEREAL AND FORAGE INSECT INVESTIGATIONS. 



W. R. Walton has continued in the leadership of the important 

 work of this section. 



European corn borer. — In August, 1921, subsequent to my report 

 of last year, the corn borer was discovered on the islands in Lake 

 Erie immediately opposite Sandusky, Ohio. Scouting operations 

 promptly showed that the insect had become established in small 



