INSECTS INJURIOUS TO TREES 



137 



specific instructions on the application of a remedy, the reader 

 is advised to write to his State Entomologist or to the 

 U. S. Bureau of Entomol- 

 ogy at Washington, D. C. 

 The letter should state the 

 name of the tree affected, 

 together with the character 

 of the injury, and should 

 be accompanied by a spec- 

 imen of the insect, or by 

 a piece of the affected leaf 

 or bark, preferably by 

 both. The advice received 

 will be authentic and will 

 be given without charge. 



When to spray: In the 

 cose of chewing insects, the 

 latter part of May is the 

 time to spray. The cater- 

 pillars hatch from their 

 eggs, and the elm leaf 

 beetle leaves its winter 

 quarters at that time. In 

 the case of sucking insects, 

 the instructions will have 

 to be more specific, de- 

 pending upon the partic- 

 ular insect in question. 

 Some sucking insects can 

 best be handled in May or 



early June when their young emerge, others can be 

 effectively treated in the fall or winter when the trees 

 are dormant. 



FIG. 99. Egg-masses of the 

 Tussock Moth. 



