186 TREES AS GOOD CITIZENS 
The spread of insects has not infrequently been due to 
their being carried on young trees from the nursery. For 
this reason it is important that all trees should be free from 
insects and diseases when they are sent from the nursery. 
Reliable nurserymen, in cooperation with state inspectors, 
endeavor to eliminate these troubles from nursery stock. 
As an added precaution many kinds can, without injury, 
be fumigated at the nursery before shipment. It should 
not be necessary to call attention to the worthlessness of 
panaceas by which all insect attacks may be prevented 
by injecting a fluid into the tree, or by driving special 
medicated nails into them. Fakers and rascals, passing as 
tree doctors, continue to extract much good money from 
a gullible public for worthless or even harmful ministra¬ 
tions. Imposition of this character has been so widespread 
as to cause more than one official warning to be issued 
against encouraging such methods. 
Insect enemies of the trees are of three types, which 
may be classified as leaf-chewers, sap-suckers and borers. 
The leaf chewers eat the foliage, the sap-suckers suck the 
plant juices from the leaves, stems, branches, trunk or 
roots, while the borers injure a tree by their tunnels making 
the openings opportunities for the entrance of moisture 
and decay, but what is more serious, often partially or en¬ 
tirely girdling the inner bark of the tree. In the three 
classes there are countless subdivisions, some of which 
require special discussion, but in general the methods of 
combating are essentially the same throughout any one 
class. 
The leaf-chewing insects may be destroyed by stom¬ 
ach poisons, applied to the leaves through spraying. The 
poison may be placed on the foliage before the insects have 
begun active operations in large numbers and be there ready 
for their first activities, contingent only on its not being 
washed off by rains. 
