TREE INSECTS AND THEIR CONTROL 205 



caterpillar is more than an inch long, with 

 red head, three black plumes, and four 

 yellow, brush-like tufts on the back. 



Community action is essential to the destruction of the tussock moth. To treat 

 one tree and neglect another will not protect even the tree which is given care, as the 

 caterpillar travels from one tree to another. All trees should be treated at the same time. 



Large Elm Sawfly 



Habits This is an insect much like a 



and caterpillar, which eats leaves 



Damage, and girdles the bark of twigs, 

 often causing a tree to have an 

 appearance of having been damaged by 

 fire. Another form of damage to the 

 leaves is the appearance of blisters, caused 

 by the habit of the female of making slits 

 in the leaves and thrusting eggs into these 

 pockets. The eggs hatch in early summer 

 and produce yellowish-white worms, 

 coiled and cylindrical, with white lines 

 down the middle of their backs. These 

 worms feed on the leaves for several weeks 

 and then bury themselves in the ground at 

 the base of the tree for the winter. Mat- 

 ing and the deposit of eggs take place in 

 the spring. 



BORING 



Remedies. If the presence of the saw- 

 flies is detected during the fall 

 or winter, they should be destroyed at 

 once, by burning the debris or rubbish in 

 which they may be hidden or by breaking 

 up the ground at the base of the tree in 

 which they may be buried, and crushing 

 them. In the spring as many as possible 

 should be picked from the foliage, or 

 infested leaves taken off and destroyed. 

 If spraying becomes necessary lead arsen- 

 ate should be thoroughly applied. 



INSECTS 



Elm Borer 



Habits 



and 



Damage 



This boring insect does great 

 damage to the Elm, and is 

 especially apt to attack a tree 

 weakened by disease or from 

 other cause. At times it becomes epi- 

 demic and may destroy the trees of an 

 entire community or neighborhood. The 

 eggs are laid singly or in groups on the 

 bark at any time between May and 

 August, by a gray, long-horned beetle 

 about one-half inch long and marked with 

 red lines and black spots. The eggs 

 hatch into very small grubs without feet, 

 and these grubs immediately tunnel 

 through the bark into the cambium layer. 

 Here they continue their boring, excavat- 

 ing wider cavities as they grow larger. 

 When these cavities encircle a limb or 

 trunk the effect is to girdle and kill. The 

 grub is white and more than an inch long 

 when grown. On reaching full growth it 

 cuts out a cell under the bark and emer- 

 ges in the spring as a beetle, making its 

 exit through a round hole which it cuts 



Method There is no way to destroy 

 of this borer except by total 



Combat, removal of such part of the tree 

 as may be infested. If the 

 attack of the beetles is discovered when 

 the infested area is small and confined to 

 the branches, it is possible to save the tree. 

 On the other hand, if the trunk has been 

 attacked there is nothing to do but cut the 

 tree down. In removing branches or cut- 

 ting down the tree it is essential that the 

 wood be burned, as this is the only way 

 to prevent the borers from migrating to 

 other trees near at hand. 



Since the borer is most apt to attack a 

 tree already weakened, one of the most 

 efficient safeguards against attack is to 

 provide each tree with proper nourish- 

 ment and protect it from injuries of all 

 kinds. 



