CHAPTER XVIII 

 ORCHARD INSECTS 



153. The San Jose Scale and Other Scale Insects. 



Probably no one insect has done such widespread injury to 

 orchard trees as the San Jose Scale.* (2). The injury is 

 often due to the fact that its presence is not suspected until 

 the tree is badly damaged. The trunk and branches of 

 badly affected trees have a rough grayish appearance as if 

 covered with ashes. By scraping the surface the soft, juicy, 

 yellowish insects will be revealed beneath the covering 

 scales. The scales may most readily be detected on the 

 fruit and leaves, on which a bright red ring appears around 

 each scale. If a single female insect is examined, for which 

 a magnifying glass will be needed, it is found to^e covered 

 by a small grayish-black, circular scale. Beneath this scale 

 may be seen a small, soft, oval, orange-colored object, 

 looking very little like an insect, which is the female; the 

 scale being merely a waxy covering. The male scale is 

 smaller and somewhat elongated. 



When the males become fully developed they transform 

 into small two-winged flies. In late spring they emerge at 

 night and fly to the females. A month later the females 

 commence to give birth to live young, which look like tiny 

 yellow mites. They crawl around for a few hours and then 

 stick their mouth-parts into the bark and their scales form 

 over them. They become full grown in about a month and 

 there are several generations in a year, so that a tree with 



* Aspidiotus pernidosus Comst. Family Coccidce, see page 64. 



287 



