JOURNAL (IF AGIOmiEAL ffiSEARCH 



DBPAP.TMENT OF AGRICULTURE 

 Vol. IV Washington, D. C, May 15, 1915 No. 2 



WILT OF GIPSY-MOTH CATERPILLARS ' 



By R. W. Glaser, 



Ento7no logical Assistant, Gipsy-Moth and Brown-Tail-Moth Investigations, 



Bureau of Entomology 



INTRODUCTION 



The present investigation of the wilt of gipsy-moth caterpillars 

 (Porthetria dispar L.) was undertaken in the hope of obtaining results 

 of economic importance. Two questions that have caused consider- 

 able speculation are, When did wilt first appear in the United States ? 

 and How did it get here? The gipsy moth was brought from 

 France to Medford, Mass., in 1869, but it did not become a very serious 

 pest before 1889, when active suppression work was begun by the State 

 of Massachusetts. However, there is no account of the appearance of 

 wilt prior to 1900, although old State records and documents have 

 been gone over very thoroughly. The writer has talked to a num- 

 ber of people, but no one seems to have seen wilt before 1900. 

 Among these was Mr. C. W. Minott, who has had much experience with 

 the gipsy moth since 1894. In response to an inquiry of the writer in 

 regard to the history of wilt, Prof. Charles H. Fernald, of the Massachu- 

 setts Agricultural College and formerly entomologist of the Massachusetts 

 State Board of Agriculture, wrote as follows : 



From the first noticeable outbreak of the gipsy moths in Medford in 1889 up to 1900, 

 when the legislature closed the work, I was in close touch with it and spent all the 

 time I could spare from my college work here. During that time I neither saw nor 

 heard of the " wilt" disease nor of anything in any way resembling it. I went down 

 there every week and was around with the men in the field in ever>^ part of the infested 

 region, and if either they or the field director had noticed an>'thing of tlie kind they 

 would surely have told me, for they all knew that we were hunting for and breeding 

 all the parasites we could find. 



1 The writer desires to express his thanks to those who rendered him valuable assistance in his work: 

 Prof. William M. Wheeler, for his encouragement and advice; Prof. Charles T. Brues, for his helpful criti- 

 cisms; Mr. A. F. Burgess, Director of the Gipsy-Moth Laboratory, Melrose Highlands, Mass.; Dr. J. W. 

 Chapman, who assisted the writer in investigating the etiology of the wilt disease; Miss Teresa Sheerin; 

 and Mr. J.J. Culver. 



Journal of Agricultural Research, Vol. IV, No. 2 



Dept. of Agriculture. Washington, D. C. May 15, 191S 



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