280 LANDSCAPE GARDENING. 



and another very few and do little injury. These insects 

 increase with astonishing rapidity; a single pair, it is said, 

 may be responsible under favorable conditions of food and 

 temperature for more than 1,000,000,000 progeny in a 

 single season. They injure plant-tissues by sucking the 

 juices of the tender parts, and when numerous all of the 

 terminal shoots are stopped in growth and the tree or 

 plant has a stunted, sickly appearance. When the leaves 

 alone are attacked, they curl and roll up, and are soon 

 covered with black substances collected from the dust of the 

 atmosphere coming in contact with the sticky surface 

 caused by the exudations of the aphides. 



Remedy. The application of kerosene emulsion with 

 force enough to drive it under the curled leaf is the most 

 satisfactory remedy. If very abundant, the 10-gal. formula 

 should be used. On small trees and shrubs, where the 

 branches can be bent down, dipping the ends into the 

 emulsion would be most satisfactory, or the strong solution 

 may be applied with a soft paint-brush. 



SCALE INSECTS. Scale insects are among the most 

 destructive of the sucking kinds, and several species are 

 very abundant. Among those most to be feared are the 

 OYSTER-SHELL SCALE and the SAN JOSE SCALE. The 

 former (Mytelaspis pomorum) , Fig. 164, is very common on 

 ash, willows, lilacs, hawthorn, and on the flowering apples. 

 In shape it resembles the oyster-shell, is of a brown color, 

 about -J of an inch long by 3 1 g wide, and injures the tree by 

 sucking the juices from the growing shoots and branches. 

 At c it is shown natural size. The eggs hatch out from 

 under the parent shell the last of June or early July, and 

 the young swarrn out and soon fix themselves on other 

 branches, feeding at this point until they reach full size, 



