TREE INSECTS AND THEIR CONTROL 209 
feeds on the tender growth and lays eggs applied in the spring, at the time of the 
on the leaves. In three weeks these eggs first appearance of the young insects on 
hatch and galls result from swellings the leaves, before the galls close up. 
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 
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 becau se of the 
size of the tree a spray of lead arsenate 
will be found effectual. 
Gipsy Moth 
(See description 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. 
