INSECTS AFFECTING PARK AND WOODLAND TREES 



INTRODUCTION 



The welfare of the human race is closely connected with that of our 

 trees, and any work h)e)kino- to their better protection makes for the 

 advancement of mankind. The vahie of our street and park trees is much 

 greater than the cost of their production, and a city or village blessed with 

 such has treasure which should be most jealousl\- guarded, since these 

 magnificent growths have an important influence in modifying climatic 

 conditions, besides adding materially to the beauty of the surroundings. 

 This is not only true in cities and villages but also in tht^ country at large, 

 particularh" in such resorts as the Adirondacks, where thousands go for 

 recreation and health. The trees in such places not only afford most 

 agreeable shelter from wind and sun, but the evaporation from the immense 

 leaf areas modifies the temperature and the exhalations from the coniferous 

 needles undoubtedly aid very much in healing diseased lung tissues. 



The protection of shade trees is a serious problem, largely due to the 

 introduction into this country of certain very destructive species, such as 

 the gipsy moth, the elm leaf beetle, the elm bark louse, the leopard moth 

 and the San Jose scale, all exceedingly injurious and all, excejit the 

 gipsy moth, well established in New York State. It is only a question 

 of time before the latter crosses our borders. The above are a few of the 

 important exotic species whicli aid such destructive nati\'e forms as the 

 white marked tussock moth, the bagworm, the fall webworm, the scurfy 

 and oyster scales and the cottony maple scale in their nefarious work. 



Injuries caused by insects. It is \er\- ditficidt for most persons to form 

 an adequate idea of the great economic importance of this group. They 

 are willing to adm't that some injury is caused, but have no adequate con- 

 ception of the enormous losses inflicted. For example, during 1834 to 

 1857, the wheat midge, Diplosis tritici Fitch, caused an estimated 



