172 OfHIO EXPERIMENT STATION: BULLETIN 154 



^ It is an admitted fact that insects prefer 



Avoid -boor environment ,, i x ii. ^ ^ t. „a 



at flanting time. ^^e weaker to the stronger plant, and 



when we consider how much more easily 



a healthy, vigorous tree withstands insect attack than does its 



weaker neighbor, it is self-evident that, if for no reason other than 



the future control of insects, we should attempt to grow strong 



trees. Much can be accomplished toward this end by not planting in 



unfavorable immediate surroundings, such as over or near a gas 



main, thus running the risk of having the tree poisoned by escaping 



gas; nor directly, under I high-tension electric wires, the injurious 



burning effects of which are well known; nor too near the street, 



where the trunks are subject to -injury; nor in soil deficient in 



plant food; nor in a half .dozen or mjOre additional situations that 



might be named. 



„, , , , . ^ Tall growing species subject to insect 



Jr'Lant to make insect x. iiu xi. iiji -l-j 



■warfare possible. ^^^ack shouldnot be planted close beside 



buildings, thus making it impossible to 

 spray them properly without covering the side of "the building with 

 the spraying mixture. This is one of the great difficulties exper- 

 ienced by a city sprg.ying department. Householders object ser- 

 iously—and justly too — to the disagreeable mixtures. Toillustrate 

 the necessity for exercising this precaution take, for instance, the 

 applying of thelime-sulfur wash,, a mixture used quite extehsively 

 as a scale destroyer. This mixture when sprayed upon a painted 

 surface combines chemically with the paint, causing some shades 

 to discolor. It is absolutely impossible to spray a tree located be- 

 side a building without some of the mixture being misplaced. 

 COMMONLY INJURIOUS SPECIES. 



It is the author's intention in his treatment of the individual 

 shade tree pests to deal with each species as briefly as possible, 

 but at the same time to afford a working knowledge for operations 

 against it. To this end the description of the various insects will 

 be confined to pointing out the characteristics most useful in dif- 

 ferentiation, and only such phases of their life histories will be 

 dwelt upon as bear directly upon our understanding of the methodsv 

 of control suggested. No attempt is made to list all of the insects 

 that may be found injuring ornamentals or farest plantings within 

 the borders of the state, but only those species are considered 

 which are at present doing datnage or those that may likely be in- 

 troduced within the near future. For more complete information, 

 no better source may be found than Memoir 8, New York State 

 Museum, entitled "Insects Aifecting Park and Woodland Trees" 

 by Dr. E. P. Felt. 



