INSECTS AFFECTING PARK AND WOODLAND TREES 



45 



which can be controlled as reacUly by collectings its white egg masses as by 

 spraying. These latter are easily gathered, and the tree once cleaned, will 

 remain so for some time, or until the caterpillars can make their way from 

 adjacent trees. Several cities in New York State have found it an exceed- 

 ingly good investment to pay children a nominal amount for collecting the 

 egg masses. The weakness of this method is that it is apt to be spasmodic 

 and the rewards are offered only during times when the caterpillars are 

 exceptionally injurious, hence the insect is allowed to increase at intervals 

 and periodically inflicts considerable damage. The city of New York pays 

 an entomologist connected with the park department, who makes a practice 

 of collecting the egg masses of this insect. This should be done in other 

 cities where this species is a pest. This method can also be applied in a 

 measure to the collection of the cocoons of our larger moths, such as the 

 promethea moth, Callosamia promethea Drury and the Cynthia 

 moth, Philosamia cynthia Drury and others. 



Borers. Hand labor is practically the only method of dealing with 

 certain borers. Dr E. B. Southwick of New York city has met with consid- 

 erable success in controlling the notorious leopard moth, Zeuzera pyrina 

 Linn., a species which has become well distributed throughout that city and 

 which infests practically all kinds of trees. His men inject carbon bisul- 

 phid, carried in an engineer's oil can, into all holes which give any indication 

 of being inhabited. The orifices are then closed with putty and other scars 

 on the trees are carefully treated. This method has also been applied with 

 a little variation in details in the case of the carpenter worm, P r i o n o x y s- 

 tus robiniae Peck, in the Buffalo parks by the late M. F. Adams, who 

 preferred to stop the entrances with soap. 



Prevention of attack by the application of a deterrent wash is fre- 

 quently advised against these insects. The treatment consists in applying 

 a wash to parts liable to attack just before the egg-laying period, for the 

 purpose of driving the females away before they deposit eggs. One of the 

 best formulas is the following: i pt. of crude carbolic acid (yi pt. refined), i 

 gal. soft soap, thin with i gal. hot water, stir in acid, let it set over night, then 



