^2 PROTECTION OF PLANTS — 1924-25 



THE OUTBREAK OF THE GIPSY MOTH IN SOUTHERN QUEBEC 



L. S. McLaine 

 Entomological Branch, Ottawa. 



So much has been written and said about the Gipsy moth situation on the 

 North American continent, much of which is undoubtedly familiar to the 

 members of this Society, that it will be necessary only to review the history of 

 this insect in the briefest manner. It was in the early sixties of the last century, 

 that a French scientist, living in the vicinity of Boston, imported some egg 

 clusters of the Gipsy moth from Europe with the intent of crossing this insect 

 with native silkworms. Some of the material escaped, and although the matter 

 was brought to the attention of entomologists and others through the medium 

 of the scientific press, no action was taken to investigate the situation. More 

 than twenty years were required for the insect to become established and for the 

 caterpillars to become so abundant as to receive public notice. Control meas- 

 ures were inaugurated and by about 1900, the infestation had been so reduced 

 that the officials in charge were in hopes that the eradication of the pest was not 

 impossible. In spite of the vigorous protests of the entomologists, who were 

 anxious for the control work to be carried on for a few more years in an endeavor 

 to eliminate the insect, the state legislature refused to appropriate any further 

 funds and the work was closed down. By 1905 the insect had increased to 

 such an extent that it was imperative to recommence control operations in the 

 field if the forest, shade and fruit tress were to be saved. A field survey of the 

 infested territory showed that the insect had spread over twenty-five hundred 

 square miles, and it was then realized that there was no hope of exterminating 

 the gipsy moth from Massachusetts. 



From that time the insect has been gradually spreading in all directions, 

 but particularly in a north easterly direction, like an ever encroaching sea, in 

 spite of the millions of dollars that have been spent by the federal, state and 

 civic authorities as well as private individuals in an effort to stem the tide. 



Canada has been keeping a close watch of the situation, and entomologists 

 realized that it was only a question of time before the Dominion would be in- 

 vaded. There appeared to be two vulnerable points in Canada where an 

 infestation of the gipsy moth, due to natural spread from the United States, 

 was likely to occur, one was in New Brunswick through the state of Maine, 

 and the second, in the eastern townships of Quebec through New Hampshire 

 or Vermont. 



In the fall of 1922 an international conference was held at Albany, New 

 York to discuss the gipsy moth situation. Officials actively engaged in the 

 gipsy moth control work and others in adjoining states who were intensely 

 interested in the problem, as the pest was gradually approaching their territory, 

 decided that it was necessarv to review the entire situation and try to work out 



