166 TREES IK WINTER 



The best way of controlling this pest is in the destruction of 

 the egg-masses during the winter. This nia}^ be done either by 

 scraping them off and burning them or by treating them with 

 creosote in the same way as described for gypsy moth eggs. The 

 pest may be controlled also by spraying in June with arsenate 

 of lead at the rate of six pounds to one hundred gallons of water. 

 By destroying the first brood in June there should be no trouble 

 from the second brood later in the season. 



SUCKING-IXSECTS. 



A2)'lus or Plant Lice — There are many species of aphis affecting 

 shade trees. As a rule different species attack different kinds of 

 trees. They are very much alike except in color. The green, 

 brown, black, and woolly forms are the most common. The insects 

 pass the winter in the egg stage and often in early spring the 

 newly hatched lice may be seen in large clusters on the swollen 

 buds and newly formed leaves. A little later the leaves curl up 

 and the insects remain inside sucking the juice from the tissue 

 of the leaf. The insects multiply very rapidly and often cause 

 much injury to ornamental trees. They secrete a sort of honey- 

 dew that collects on the foliage and often drops to the ground. 

 A fungus often develops on this sweet secretion giving it a black, 

 unsightly appearance. 



This pest seldom becomes so serious as to require treatment, 

 but may be controlled, if remedial measures are necessary, by 

 spraying with kerosene emulsion as soon as the young lice appear 

 and before the leaves begin to curl. Fine tobacco powder blown on 

 the trees after the leaves have curled will be found helpful in 

 controlling the pest. The use of whale-oil soap, at the rate of 

 one pound to five gallons of water, is recommended Avhere only a 

 small amount of spray material is required. It costs a little 

 more than kerosene emulsion, but is more conveniently prepared. 



The Spruce Gall Louse is different from the other species of 

 this class in that it builds galls on the growing twigs. In some 

 sections it has become a serious pest of the N'orway Spruce. The 

 Black, White, and Blue Spruces are also subject to attack. The 

 eggs are laid about May first, the young lice appearing about a 

 week later and settling at the base of the new shoots. By some 

 peculiar form of irritation produced by the insects, a gall-like 

 swelling is produced. Concealed within these galls the insects 



