EXPERIMENT STATION BULLETINS. 277 



a pin point. If it is the San Jose scale it can be easily lifted or rubbed 

 off, and the skin beneath will be smooth and unbroken and of a greenish 

 color, while if it is not the scale it cannot be removed without tearing 

 the skin, which will be rough and broken. The spots referred to are 

 generally the result of slight injuries, and the dots are a sort of corky 

 growth developed to repair the injury. Other scales also cause a similar 

 discoloration of apples. The most common is the scurfy scale, but this 

 can be readily distinguished from the San Jose, as it is grayish-white, 

 generally somewhat heart-shaped and several times as large as the San 

 Jose scale. 



During the latter part of the summer the San Jose scale propagates 

 very rapidly and even though there were only a few upon the trees in 

 the spring they may be entirely covered by the close of the season. 

 Examination of an infested tree during the winter and spring will reveal 

 the presence of small black dots, often so thick as to overlap one an- 

 other. They will be circular in form and of about the size of an ordinary 

 period (.). If examined with a hand lens a circular groove will be 

 noted around the center which will have something of the appearance of 

 a nipple. Other scales that slightly resemble the San Jose have a point, 

 usually at one side of the center which is of an orange or yellow color. 

 These scales are usually larger than the San Jose, and are more or less 

 oval in form and grayish or brown in color. 



HOW IT LOOKS ON THE BRANCHES. 



If the shell-like covering of the San Jose scale is lifted ofif, the living 

 portion of the scale will be found beneath. This in a general way re- 

 sembles a very small larva of a potato beetle, except that it is yellow in 

 color and is filled with a yellow, oily fluid, to such an extent that if the 

 thumb nail is rubbed over where there are a considerable number of the 

 scales a substance that resembles melted butter will exude in noticeable 

 quantities. This test is sometimes used to determine the presence of 

 the scale and the relative number that have been killed, but for the 

 latter purpose it is not very reliable. 



In order that one may be positive regarding the presence of the San 

 Jose scale a good pocket lens is desirable. Something that will answer 

 the purpose can generally be found at an optician's for fifty cents. 

 Having in mind that the scale is round, flattened, black, and with a 

 small nipple at the center, one is prepared to examine the trees and learn 

 if they are infested. It should also be noted that when the scales die 

 the shells take on a gray color so that a tree that has been infested for 

 a number of years will look as if coal ashes had been thrown over it. 



From the fact that the scale prefers the soft growth and that the 

 young branches are easiest injured by their punctures, the tops of the 

 trees die first. The leaves turn yellow and drop off and when the trees 

 are badly infested they will generally die during the winter. As the 

 trunks and larger branches are still full of life, water-sprouts are often 

 sent up from the main crotches of young trees, so that they have a lux- 

 uriant appearance although the tops of the trees are dead. Tliis makes 

 it possible to save trees that have been quite badly injured by the scale, 

 by cutting off the injured branches and forming a new head from the 

 water-sprouts that will soon form. It will be an easy matter to spray 



