The Apple. 57 



the numerous punctures thus made cause wart-like ex- 

 crescences ou the bark. In cases of severe attack the leaves 

 turn yellow and drop and sometimes the trees die. 



The winged females, which appear in autumn, fly from 

 tree to tree to deposit eggs for another generation the fol- 

 lowing spring. The lice can endure considerable frost, 

 and in mild climates pass the winter about the base of in- 

 fested trees. This form of the insect is readily destroyed 

 by two thorough sprayings with strong kerosene emulsion, 

 or if onl}' the trunk of the tree is infested, by applying the 

 emulsion with a whitewash brush to this part. 



The root-inhabitnig form is a more serious pest where it 

 abounds, than the aerial form. Infested trees are indicated 

 by pale or yellowish, scanty foliage and feeble growth. 

 Unless relieved, they sooner or later die or blow over by 

 the wind. By removing earth from the roots near the 

 base of the trunk, the lice will be found in clusters about 

 and between the roots, which have grown knotty and dis- 

 torted from the continual drain upon their juices by the 

 lice. The roots thus injured soon perish and decay, and 

 the tree, if large, is blown down by the first hard wind. 



Tobacco dust used about the roots is a specific for the 

 root form of the woolly-aphis^ Infested orchard trees may 

 be cleared from it by removing the earth about their roots 

 to the depth of 4 inches, and to a distance of 2 feet from 

 the trunk, and scattering 5 or 6 pounds of tobacco dust 

 over the bottom of this excavation, after which the dirt 

 should be replaced. In much infested regions 2 or 3 pounds 

 of toljacco dust should be applied each spring, to each or- 

 chard tree, as abov^e directed, to prevent attack; nursery 

 apple trees should have a liberal application of tobacco 

 dust about their roots each spring, removing some of the 



