TREES, SHRUBS, VINES AND PLANTS. 385 



When the galls first appear on a tree, it is generally best to pick 

 them off and destroy them. When they are abundant, this meth- 

 od becomes no longer practicable, and a thorough spraying with 

 two pounds of soap dissolved in a gallon of water, applied about 

 the third or fourth week in April, is the best treatment available. 



THE OYSTER-SHELL SCALE. 



This scale insect attacks the willow, poplar, ash, lilac, and sev- 

 eral other ornamental trees and shrubs, besides the apple, and fre- 

 quently destroys the tree it is on. The scale covering the insect is 

 bluntly pointed at one end, rounded at the other, two or three 

 times as long as broad, and generally more or less bent toward one 

 side, somewhat resembling an oyster-shell in form. It varies in 

 color, but is some shade of gray or brown. During the winter the 

 scale shelters beneath itself the dead female insect which formed 

 it, together with from thirty to one hundred pale straw-colored 

 eggs. These eggs hatch between the middle of May and the tenth 

 of June, according to the latitude, climate and advancement of the 

 season, and the very minute whitish young crawl about seeking for 

 places where they may settle down to feed. When such places are 

 found, they thrust their beaks through the bark and begin to suck 

 the sap from the plant. A scale now begins to be formed over 

 the back of the insect, which becomes adult by fall. The eggs are 

 laid under the scale and the insect dies. 



In the more northern states these eggs remain under the scale 

 till the following year, before hatching. Further south they may 

 hatch the same season, giving a second generation the same year. 



The fact that the eggs of this pest all hatch at about the same 

 time is made use of in the treatment employed, which is to spray 

 very thoroughly as soon as the eggs hatch at which time the 

 tiny whitish young can be seen crawling around, if looked sharply 

 for with linseed oil emulsion, made as follows: 



Hard soap, 1 pound 



Raw linseed oil, 1 gallon 



Water to make 12 gallons 



Dissolve the soap in a small quantity of warm water, add the 



