TREE INSECTS AND THEIR CONTROL 185 



Of still greater value is the active cooperation of the local 

 authorities in detecting and fighting the insect enemies, 

 and this value lies not only in the matter of technical 

 knowledge but in the facilities for active combat, as well. 

 The owner of a single tree rarely wants to go to the expense 

 of buying equipment for spraying and other forms of 

 treatment. For the municipal government to handle this 

 work for all taxpayers reduces the problem to its simplest 

 terms and produces the greatest degree of efficiency with 

 the least cost to the individual. 



The importance of municipal treatment of insect pests 

 is emphasized by the way many insects spread. It is not 

 uncommon for all the trees of a given variety to be affected 

 throughout an entire community. Treatment of an indi- 

 vidual tree in the event of such an epidemic obviously 

 accomplishes nothing. The elimination of the visitors 

 from that particular tree may be complete, but renewal of 

 the attack will be made by emigrants from infested neigh- 

 boring trees which have not been treated. The only effec- 

 tual measure is to treat all trees of the infested species, and 

 this, of course, cannot be satisfactorily accomplished 

 without centralized authority and action. This consti- 

 tutes one of the unanswerable arguments in favor of mu- 

 nicipal control for street shade trees, however small the 

 community. 



In the absence of a branch of the local government 

 prepared for such work, it is important for the individual 

 property owners to act in close cooperation among them- 

 selves, to achieve the best possible results and to minimize 

 the cost to each of them. Community ownership of spray- 

 ing apparatus and other equipment, and community 

 action in undertaking to overcome insect attacks, will lead 

 to a solution of many of the tree owners' most serious 

 problems. 



