TREE INSECTS AND THEIR CONTROL 217 
Gray Aphis 
This is a large plant louse nearly yi 
inch long. It collects in masses on the 
under side of branches, sucking sap and 
exuding a honeydew more pronounced 
and objectionable than that of the Nor¬ 
way Maple aphid. They appear in mid¬ 
summer and increase until frost. They 
are not likely to kill the tree but branches 
may succumb where the infestation is 
severe. It is also sometimes seen on the 
Linden and on the Pin Oak. 
The treatment is the same as for other 
aphids. 
SAP-SUCKING SCALE INSECTS 
Pubescent Oak Kermes 
Habits This sap-sucking scale insect 
and confines its attacks to twigs 
Damage, and leaves, and does no dam¬ 
age beyond checking growth. 
It appears on Oaks only. The young 
insects, hatched late in the fall, spend the 
winter on the bark. In the spring, when 
White Oak buds begin to open, the insects 
attack the new leaves and tender young 
growth. The attack causes crumpling, 
and later in the season death results to 
the parts affected. The older leaves and 
twigs are studded with stationary brown, 
pea-shaped scale insects. Some of the 
leaves which have been killed remain on 
the tree all winter. 
Remedy. A simple means of control 
is spraying with a solution of 
one part of miscible oil to 15 parts of 
water. This should be applied when the 
insects appear in the spring, at the time 
White Oak buds begin to open. 
Obscure Scale 
Habits This sap-sucking scale insect Remedy. Winter spraying with mis- 
and has much the same character- cible-oil solutien is effectual 
Damage, istics and appearance as the in the control of this scale. 
Gloomy Scale, (see Maple), 
but is somewhat coarser. Its attacks are 
confined to Oaks, and it sometimes does 
serious damage to young trees and bran¬ 
ches. In the case of severe infestation 
it may cause the death of the tree or the 
affected parts. 
GALL INSECTS 
Oak Galls 
Habits The Oaks are especially 
and subject to the visitations of 
Damage, gall-making insects affecting 
all parts of a tree from roots to 
buds. The galls produced by these insects 
are swellings of various shapes and sizes, 
Treatment. No action is necessary, 
unless a fine tree is infested 
repeatedly for several years. In such a 
case the gall-laden parts should be cut and 
burned. The fallen leaves bearing the 
galls should be burned as well. 
