INSECTS INJURIOUS TO ORCHARD FRUITS 



473 



therefore, that a tree with but a few scales on it in spring will 

 be covered by them and the fruit unfit for market in the fall, 



FIG. 396. Peach leaf bearing $an- Jos6 scales, along veins. 



and that with these millions of little beaks pumping out the sap 



and poisoning the tissues a tree soon succumbs. 



The pest has been spread mostly by being transported on 



nursery trees. Trees infested from the nursery will usually have 



more scales on the lower trunk, 

 from which they will spread 

 to the limbs, while those infested 

 from neighboring trees will have 

 more scales on the young wood. 

 Where the pest is abundant 

 the young insects are undoubt- 

 edly blown from tree to tree by 

 the wind, or they may be carried 

 on the feet of birds or insects, 

 or brushed off and carried by 

 persons or teams working in the 

 orchard. The insect has been 

 found on a long list of plants, 

 but on many of them it is 



largely accidental. Injury is practically confined to plants of the 



Rosace ce, which family includes all our common deciduous fruits. 



Of the orchard trees peach, pear, Japanese plum, apple and 



quince are most injured in the order named, while cherry and 



European plum are less injured. 



Control. As yet no spray has been found for use in summer 



which will more than check the increase of the pest without 



injury to the tree, and summer spraying is resorted to only when 



FIG. 397. Adult female San Jos6 

 scale, with scale removed to ex- 

 pose the insect. (After Alwood.) 



