54: 



Zessons in Fruit Gi^owing. 



appear to tlie unaided eye as mere specks, leave the scales 

 and scatter themselves over the twigs and foliage of the 

 tree, subsisting on its juices. Later they largely congre- 

 gate about the base of the side shoots of the terminal twigs, 

 where they gradually secrete the scale beneath which the 

 eggs are deposited, and remain until the following spring. 



Preventive measures. Potash dissolves the scales, and 

 kerosene destroys both the eggs and the lice. 

 By spraying before the leaves appear in spring 

 with a kerosene emulsion containing an abund- 

 ance of soap, the great majority of the eggs 

 will be destroyed. Watch should be kept dur- 

 ing the latter part of spring for the appearance 

 of the young lice. If these hatch in lai*ge num- 

 bers a second spraying with the same material 

 should be given. Unthrifty trees should bo 

 restored to vigor by improved cultivation, ma- 

 nuring or stimulative pruning, as is most 

 needed. Often the restoration of vigor re- 

 moves the greater part of the lice. Young trees 

 infested with bark-lice should not be planted 

 unless treated with the kerosene emulsion. 



60. The San Jose scale {Aspkliotus pemichsus) (Fig. 15) 

 is a minute scale insect destructive to nearly all fruit trees 

 and plants grown in the United States and Canada. On 

 much-infested branches, the scales appear as a grayish, 

 slightly roughened, scurvy deposit which, when crushed 

 by scraping, yields a yellowish, oily liquid. Affected twigs 

 examined with a good hand lens during summer show 

 orange-colored larvae running about, and snow-white young 



1 Oyster-shell-bark louse as it appears on twig of apple. (After Saunders.) 



