1921 ENTOMOLOGICAL SOCIETY. 43 



by the audience in the discussion that followed. The second event of the evening 

 was the reading of the continuation of Mr. Morris' delightful "Life History 

 of a Hobby Horse." Mr. Morris captivated his audience by the charm of his 

 language and delivery, and the fine scholarship and whimsical humour whier 

 characterised his address. 



Dr. Felt's paper appears below, while Mr. Morris's "Hobby Horse" which 

 was commenced in our Report for 1918, is being continued in the "Canadian 

 Entomologist," in the series of papers on "Popular and Practical Entomology." 



The meeting was enlivened by several musical selections played by the 

 College Orchestra. 



SOME OF THE BROADER ASPECTS OF INSECT CONTROL. 



E. R. Felt, State Entomologist of New York. 



This is not so much a contribution as a general consideration of the primary 

 function of the economic entomologist, namely, the more effective eontrol of 

 injurious insects. 



Insect abundance depends upon a certain prolificacy, sufficient suitable food, 

 favorable climatic conditions and relative freedom from the operation of checks 

 of one kind or another. 



Very limited reproduction prevents an insect from becoming economically 

 important and such species therefore usually escape notice. 



A sufficiency of suitable food is necessary, and we desire in this connection 

 to call attention to the adjective, suitable, because food habit limitations are 

 often more real than apparent. There is need of distinguishing between plants 

 upon which a species thrives and those upon which it can just maintain itself, 

 or where this is true only of some of the older larval stages. In the case of 

 borers there is a marked economic difference between real food plants and 

 "shelter" plants. 



Although some insects can withstand great extremes, it is a fact that most 

 economic species are greatly affected by climatic conditions, and some respond 

 so readily that it is difficult to recognize the cause for the difference in behaviour. 



Controlling factors, aside from climate noted above, are susceptible of 

 modifications in some cases and deserve most careful consideration. 



The past twenty-five years have witnessed notable improvements in both 

 spraying outfits and insecticides. Compare for example, the hand sprayers and 

 blowers of the earlier days with 'the large power spraying outfits and dusters of 

 the present time; and recall the development and extensive use of arsenate of 

 lead, lime sulphur wash and nicotine sulphate, all important and extremely 

 valuable additions to the pharmacopoeia of the oconomic entomologist. 



It is quite within possibilities that the airplane may be used for distributing 

 poisons over forest areas, and perhaps extensive orchards, and investigations of 

 insectides indicate continued progress in the search for and development of 

 materials which can be used for the better control of insect pests. 



The profound influence of climate must be taken into account. It is well 

 known that cool, backward weather conditions in the spring greatly reduce the 

 numbers of certain insects, for example, the first generation of the San Jose 

 6cale and the elm leaf beetle; and in the case of the former, adverse winter 



