208 TREES AS GOOD CITIZENS 



lemon-yellow. They settle on leaves and 

 twigs, feeding there until late summer, 

 when they return to the trunk or larger 

 limbs. 



GALL INSECTS 

 Gall Aphids 



Habits These sap-sucking insects Remedies. Spraying is seldom neces- 

 and disfigure a tree by causing the sary but if desired a tree may 

 Damage, growth of swellings known as be sprayed with kerosene emulsion or mis- 

 galls. These galls sometimes cible oil solution. If the galls appear on 

 become so numerous as to create alarm, more than one tree in a neighborhood all 

 but the damage is more to appearance of those infested should be treated, 

 than to growth or vitality. A tree is sel 

 dom harmed in health by them. 



GUM (SWEET) 

 LEAF-CHEWING INSECTS 



Forest Tent Caterpillar 

 (See description and remedies under Elm) 



HACKBERRY 



LEAF-CHEWING INSECTS 



Spiny Elm Caterpillar 

 (See description and remedies under Elm) 



Hackberry Butterfly Caterpillar 



Habits This leaf-chewer causes ser- Remedies. These caterpillars fall to 



and ious damage to the foliage of the ground with the dropping 



Damage, the Hackberry. Two genera- leaves in the autumn and it then becomes 

 tions develop yearly, from a simple matter to destroy them by raking 

 eggs deposited on the leaves. The cater- and burning the leaves. Spraying the 

 pillar is green in color, with pale spots and tree with lead arsenate while the eater- 

 lines along the back and projections at pillars are feeding is also a means of 

 each end. It is found on the under side control, 

 of the leaf. At maturity the caterpillar 

 develops Into a russet gray butterfly, 

 spotted with brown. The presence of the 

 caterpillar is indicated by the damage 

 resulting from its leaf-eating habits. 



GALL INSECTS 

 Hackberry Gall Insects 



Habits The galls produced by this Remedies. It is not often necessary to 



and insect mar the appearance of a apply treatment against this 



Damage, tree by disfiguring the foliage, insect, as the damage is usually slight, 



but otherwise they do no par- When treatment is needed the tree should 



ticular harm. In the spring, when the be sprayed with kerosene emulsion or 



buds begin to swell and open, the insect water-soluble oil. The spray should be 



