28 



Where water pressure is not available, the trunks of the trees may 

 be sprayed with strong soap suds of any kind, or with any of the 

 dilute oil mixtures. 



BORERS. 



Shade and fruit trees are equally subject to the attacks of borers 

 that feed beneath the bark or in the wood tissue. Sometimes the 

 trunks are attacked; sometimes the branches, and occasionally the 

 roots. Sometimes, beneath the bark, there will be shallow, irregularly 

 winding galleries, ending in a larger, shallow chamber. This gallery 

 is made by a flat -headed borer, called so because the anterior segments 

 are broader than the rest of the body and much flattened, so that it 

 can live in the shallow channel that it has made. Insects of this 

 character usually attack weakened trees only. 



Sometimes, also beneath the bark, we find a series of narrow 

 borings — a single up-and-down gallery; one, two or three inches in 

 length and about one-sixteenth of an inch in diameter, and, branching 

 from this center, a large number of laterals, sometimes extending at 

 right angles to the center and sometimes branching in every direc- 

 tion, but always so that they do not cross each other and gradually 

 separate as they extend from the common center. The main gallery 

 in this case has been made by a bark beetle, which laid its eggs on 

 each side close together, and the lateral galleries have been made by 

 the larvae which hatched from the eggs. These pests also,* as a rule, 

 attack trees which are in a more or less weakened condition. This 

 is not universal, applied to bark beetles as a whole, but it is the rule 

 as applied to those that work in the shade and fruit trees that are 

 usually planted. When a tree becomes badly infested by these beetles 

 it might as well be cut out at once. The fact that it was attacked at 

 all is an indication of weakness, and as the attack continues the tree 

 becomes even more weakened and further subject to infestation until it 

 dies. Borers of this kind are very apt to attack hickory and other 

 forest trees growing in lawns or under such conditions that they do 

 not receive a full supply of moisttire and plant-food. The most de- 

 structive species on city shade .treees is the 



