TREE INSECTS AND THEIR CONTROL 209 



feeds on the tender growth and lays eggs 

 on the leaves. In three weeks these eggs 

 hatch and galls result from swellings 

 caused by the attacks of the young insects 

 in feeding. The galls produce deformities 

 on leaves, leaf-stems and twigs. 



HICKORY 



LEAF-CHEWING INSECTS 

 Walnut Caterpillar 



applied in the spring, at the time of the 

 first appearance of the young insects on 

 the leaves, before the galls close up. 



Habits This leaf-chewing caterpillar 



and sometimes strips a tree of all 



Damage, its leaves. Its favorite is the 

 Walnut, but it also attacks the 

 Butternut and the Hickory. In extreme 

 cases of repeated yearly attacks the death 

 of the tree results. The caterpillars hatch 

 from eggs laid by moths in July on the 

 underside of leaves. Upon hatching the 

 caterpillars attack the leaves and continue 

 to feed until early fall. In full growth the 

 caterpillar is nearly two inches long. It is 

 black and covered with hairs of a dirty 

 gray color. 



Remedies. The simplest remedy, 

 where possible, is to collect 

 the caterpillars while they are on the tree. 

 Where this can not be done because of the 

 size of the tree a spray of lead arsenate 

 will be found effectual. 



(See description 



Gipsy Moth 



and remedies 



under Beech) 



BORING INSECTS 

 Hickory Bark Beetle 



Habits This boring insect is a seri- 



and ous menace to the Hickory, 



Damage, frequently causing the death 

 of trees. The beetles are 

 hatched from eggs laid, about the time the 

 pollen falls from Hickory tassels, in cells 

 at the sides of a vertical channel exca- 

 vated by the parent beetle between the 

 inner bark and the wood. At first the 

 grubs feed on the inner layer of bark and 

 tunnel the surface of the wood on either 

 side of the vertical channel, producing a 

 design resembling a centipede. In case 

 of severe infestation these tunnels may 

 completely girdle a tree and cause its 

 death. Later the grubs tunnel toward the 

 surface of the bark, where they winter, 

 emerging in the spring as beetles. The 

 work of the insect is indicated by damage 

 to leaves at the base of the leaf-stems, in 

 the spring, and by clean round holes in 

 the bark; the foliage fades and dies in 

 early autumn. 



14 



Control. It takes a vigorous tree to 

 combat this enemy, and for 

 this reason it is important to keep Hick- 

 ories in good condition. In case of slight 

 attack, an efficient aid to control is to 

 stimulate the vigor of the tree by use of 

 fertilizer, thus enabling the tree to resist 

 the damage. Keeping the trunk covered 

 with strong whale-oil soap-suds will prove 

 helpful. If a tree is seriously affected it 

 should be cut down and burned, to pro- 

 tect neighboring trees from infestation. 



