TREE INSECTS AND THEIR CONTROL 217 



Gray Aphis 



This is a large plant louse nearly ^ 

 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 



and has much the same character- 



Damage, istics and appearance as the 

 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. 



Remedy. Winter spraying with mis- 

 cible-oil solutien is effectual 

 in the control of this scale. 



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. 



