INSECT ENEMIES OF SHADE TREES. 



H. T. FERNALD. 



It is impossible to adequately consider in detail even the more 

 important pests of shade trees within the limits here assigned. Over 

 five hundred different insects feed on various kinds of oaks; the 

 elm, maple, evergreens and other important trees each have many- 

 enemies ; and a few general remarks and a more detailed considera- 

 tion of the most important insects is all which can be given. 



Two fundamental principles underlie methods of treatment. For 

 insects such as caterpillars and others which feed on the leaves, 

 spraying with arsenate of lead is usually a success, though if the 

 feeding is not noticed until the insects have nearly finished their 

 work, the results will hardly be satisfactory. Where the insects are 

 feeding in clusters, it is often cheaper and easier to gather the clus- 

 ters by hand and destroy them than to spray ; and there are 

 some leaf feeders whose habits are such that neither hand picking 

 nor spraying is the best method of control, and special treatment for 

 each case is necessary. 



For insects which do not feed on the leaves, but suck the juices, 

 arsenate of lead is useless, as such forms get none of the poison into 

 their bodies. Accordingly, something which kills every insect it 

 touches, and which is called a contact poison, is used instead. Kero- 

 sene and soap are most often used in this way, and directions for 

 making a few of the most successful sprays are given at the end of 

 this article. 



In general then, if caterpillars, grubs or insects in any stage are 

 eating the leaves, spray with arsenate of lead if they are scattered, 

 or pick them off if they are in clusters; for sucking insects, like 

 plant lice, scales, etc., spray with a contact poison. 



Failure to observe three points is responsible for nine-tenths of 

 the poor results from spraying. These are : i. Be sure the spray 

 material is properly made. 2. Apply thoroughly. 3. Apply at the 

 rififht time. 



