APPLE INSECTS 171 



poured into the required amount of water and quickly form, 

 upon stirring slightly, a perfect and stable emulsion-like mixture 

 ready for use. None of these sprays recommended for use on 

 dormant trees can be safely used on trees in foliage. Where 

 very large, old, rough-barked apple trees are infested, only the 

 most thorough kind of spraying will conquer the pest. On such 

 trees it is recommended to use the crude oil emulsion spray just 

 as the buds are swelling in the spring. 



The most effective work can be done with about 100 pounds 

 pressure per square inch, using a fine spray through a nozzle of 

 the cyclone type. The judicious pruning away of the tops and 

 long sprawling branches of infested trees will often enable the 

 orchardist to do more thorough work. Remember that the 

 San Jose scale is not larger than a pin head ; that the insect itself 

 is well protected under the scale ; and that it is therefore 

 necessary to hit each tiny scale so thoroughly that the spray 

 covers the insect. To do this requires powerful pumps, good 

 nozzles and, most important of all, an experienced and 

 determined man behind the gun who can shoot straight and 

 thoroughly cover the bark of the tree with the spray from the 

 surface of the ground to the tips of the smallest twigs. 



Reference 



U. S. Bur. Ent. Bull. 62. 1906. 



Nearly every Agricultural Experiment Station has published 

 bulletins or circulars giving full directions for fighting the San Jose 

 scale under local conditions. 



The Oyster-shell Scale 

 Lepidosaphes ulmi Linnaeus (Mytilaspis pomorum Bouche) 



This cosmopolitan insect is doubtless the commonest, most 

 widespread and best known of the scale-insects infesting fruit- 

 trees in America, where it has been injurious in the northeastern 



