170 OHIO EXPERIMENT STATION: BULLETIN 194 



The city tree under the most favorable condi- 

 City trees unhealthy, tions must keep up a continual fight for exist- 



ence. Impure, smoke-laden atmosphere; poorly 



watered and badly ventilated root system; the careless, thoughtless 

 mutilation by teamsters and passers-by, all tend to weaken it. If 

 in this weakened condition it becomes the subject of attack, it is 

 poorly fitted to withstand the burden and, unless assisted, stands a 

 poor show to win out in its fight for existence. 



INSECT CONTROL DIFFICULT IN CITIES. 



. The application of insecticidal measures is a 



Individual -work task under most dty conditions , es _ 



, 



of householders pecially SQ if the var ious householders attempt 

 e ' the operation individually. It is usually the 

 case that a few trees only are located in each yard, and frequently 

 these trees are tall, thus requiring a strong, expensive spraying 

 apparatus for treating them properly. Besides the sprayer the ser- 

 vice of two men is required, at least one of whom should have a 

 knowledge of machinery and the preparation of insecticides to in- 

 sure best results. It is only in the case of large lawns that it would 

 be practicable for private individuals to own and operate spraying 

 outfits. 



However, in a few instances, designated in the description of 

 the various shade tree pests following, it is possible for the house- 

 holder to furnish effective assistance, and to do so with small ex- 

 penditure of time and money. 



7j .. The more desirable and practicable ar- 



A municipal tree-treating ,. . . 



department desirable. rangement is for the city to support a tree 



spraying department, operated by com- 



petent, experienced men, whose business it is to look after the 

 public trees and who are prepared to do spraying on private grounds 

 for a reasonable charge. Such departments are already in existence 

 or are under way of organization in some of our principal cities, 

 the department at Cleveland being the most complete in this state. 

 CORRECT PLANTING THE FIRST STEP TOWARD INSECT CONTROL. 



From the standpoint of the future control of insect pests, two 

 things should be considered in the planting of a shade tree; the 

 species of tree and the location of planting. 



All kinds of shade trees are not equally 



Some trees more suscep- . 



,.,,,. ., r susceptible to insect attack, some being 



tible to insect attack . . , . , , 



., ., almost immune, others so highly suscep- 



than others. .... 



tible to attack from one or two species 



that it is impossible to grow them, while still others are the prey of 

 a whole host of depredators. 



