1907.] PUBLIC DOCUMENT- -No. 73. 129 



other words, the history of such diseases shows that, to be 

 effective, they must be favored by climatic conditions; and 

 that man can do but little in artificially spreading them, unless 

 such favoring conditions prevail. 



It should be stated that the fungous disease was very effec- 

 tive against the larger caterpillars during the summer of 1906, 

 killing them by thousands ; and that it was still present on the 

 winter webs in the fall, although not so conspicuous as in the 

 fall of 1905. It is also desirable to mention that there is but 

 little if any ground for the popular belief, exploited in the 

 newspapers in the winter of 1905-06, that the presence of 

 dead caterpillars on the outside of the webs is caused by the 

 emerging of the insects during mild weather and their subse- 

 quent death by freezing. The death of the caterpillars in 

 practically every case was effected by the disease. 



While this disease has been of great help in reducing the 

 numbers of the brown-tail moth, it has given rise to certain 

 unexpected complications in connection with establishing the 

 imported parasites of this insect. At least two important Eu- 

 ropean parasites, which we have introduced, winter in the webs 

 of the moth. In the colonies where these parasites have been 

 liberated by thousands, the disease has been so prevalent as to 

 reduce greatly the number of winter webs, and the consequent 

 opportunities for the successful hibernation of the parasites. 



AID. 



On Dec. 4, 1905, the Hon. Ernest W. Roberts, representa- 

 tive from the Seventh Massachusetts District, introduced in 

 the national House of Representatives two bills, numbered re- 

 spectively 285 and 286, the one carrying an appropriation of 

 $250,000, to be expended under the direction of the Secretary 

 of Agriculture for the purpose of exterminating or controlling 

 the gypsy moth and brown-tail moth; the other carrying an 

 appropriation of $15,000, to be expended under the direction 

 of the Secretary of Agriculture for the purpose of investi- 

 gating and importing natural enemies of the moths from Eu- 

 rope and Asia. 



By direction of His Excellency the Governor the claims of 

 Massachusetts for national aid in controlling the moth pests 



