362 



REPORT OF STATE BOARD OF HORTICULTURE. 



is usually stained deep red or purplish, and when the scale is only scatter- 

 ingly present the distinctive purplish ring- surrounding- each is almost as 

 noticeable on young twigs as on fruit, and is of the greatest service in 

 facilitating- the inspection of trees which have been subject to possible 

 contagion. The almost microscopic young scale might easily elude the most 

 ©areful search, but the striking circling ring makes them comparatively 

 conspicuous objects without the aid of a glass. 



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Kig 2— Appfai-ance of scale on bark : a, infested twig, natural size ; b, bark as 

 It appears under hand lens showing scales in various stages of development 

 and young larva>. (Original). 



If the tree survives the attack the infested wood eventually becomes 

 knotty and irregular, partly from the sapping of the juices by the insect and 

 also without doubt largely from the poisoning of the sap of the cambium 

 layer by the punctures of the insect, as indicated by the discoloration. 

 Young peach trees will ordinarily survive the scale only two or three years. 

 Pears are sometimes killed outright, but generally maintain a feeble, sickly 

 existence, making little or no growth for a somewhat longer period. 



