365 



AN ATTEMPT TO CONTROL INSECT PESTS BY THE 

 INTRODUCTION OF PARASITES. 



Tlw liuportidion into the United States of the Puraaites of tlie Gipsy Moth, 

 mid the Bronm-tail Moth — « Report of Progress. By L. O. Howard aiul 

 W. F. Fiske. Bureau of Eutomology, U. S. Department of Agriculture, 

 Bulletin no. 91, pp. 1-312, July 29, 1911. 



lu the introduction to this voluminous report the senior author states that 

 no work of this magnitude has been hitherto attempted and discusses similar 

 work elsewhere. Success in parasite introduction, apart from work against 

 fixed scale insects, has been limited to the parasites of the sugar-cane leaf- 

 hopper in Hawaii, " some reported work " in introducing South American fruit- 

 fly parasites to Australia, and the transfer to California of one parasite of codliu 

 moth from Spain. " It seemed to the writer that by attempting to reproduce in 

 New England as nearly as possible the entire natural environment of the gipsy 

 moth and the brown-tail moth in their native homes, similar conditions of 

 comparative scarcity could surely be reached, and this view he still holds with 

 enthusiasm." (L*. 0. Howard). That is to say, an endeavour was to be made 

 to reduce these two moths, which now occur in the United States in enormous 

 mmibers, to the condition of comparative rarity which they exhibit in Europe, 

 by reproducing as nearly as possible their natural environment, so far as their 

 insect enemies are concerned. 



The initial idea vvas to send to America large quantities of caterpillars, and to 

 rear from them parasites, which would then be let loose in localities where the 

 pests abounded and would breed there. It was hoped by this means to establish 

 in America the parasites that check these species elsewhere. This method, which 

 seems a simple one, was decided upon partly because the moths themselves were 

 introduced and established so casually, and it was thought it would be quite easy 

 to introduce their checks. Gipsy moth was brought to Massachusetts in 1868 or 

 1869 and escaped by accident. For 10 years it attracted little notice, then it 

 increased, and in 1889 it became a serious pest. From that date until 1900, 

 up to a million dollars a year was spent in fighting it ; then the operations were 

 susjjended for five years, and in consequence the pest spread from an area of 

 3.59 square miles over 2,224 square miles. In 1905 the present effort was 

 commenced by the Federal Department. 



Brown-tail moth was introduced in the early '90's and has sjjread rapidly as 

 the females fly readily. 



The author goes into considerable and unnecessary detail over his travelling in 

 Europe and the arrangements made to start the work. One of the things learnt 

 after a few years was that it was not a simple matter to establish parasites ; a 

 small colony simply put out in a locality disappeared in many cases, due apparently 

 to dispersal so rapidly that they did not find mates. It was found that it was 



