77 



It should be noted that scales remain on the tree a long 

 time after the insects which produce them are dead, before 

 weathering off, so that a tree largely freed from these pests 

 may appear badly infested when this is really not the case. 



The San Jos& Scale. 



The San Jose scale has been present for nearly thirty years 

 in this State, and has caused much loss in apple orchards, as 

 when abundant it i's a very serious pest. Fortunately, most 

 apple growers are now able to recognize this insect and know 

 how to treat it. 



The fully formed scale is nearly circular, quite flat, but 

 rising gradually from its edge toward the center where there 

 is a hump or nipple, usually surrounded by a slight depression. 

 Its color at this time is generally brown or dark gray. At the 

 beginning of winter, scales of various ages may be present on 

 a tree, but the younger and the oldest ones die during this 

 period, leaving only those from one-third to two-thirds grown 

 to continue the race the following season. 



These insects under their scales resume their sucking of the 

 sap from the tree in the spring and become adult in June. 

 The production of young now begins, and here there is an 

 important difference in the life of this insect from that of the 

 oyster-shell and scurfy scales, whose eggs all hatch at about 

 the same time. With the San Jos6 scale no eggs are laid. 

 Instead, this insect produces living young, a few every few 

 days for a period of about a month, the total number per 

 female being about a hundred. These crawling young resemble 

 those of the other scales in size and structure, but are bright 

 lemon yellow in color and can be recognized in this way. Their 

 habits at- first are like those of the other kinds, but, after 

 settling down to feed, they form a pure white waxy scale over 

 themselves, circular in outline, so that in this stage they look 

 like very tiny dots of white wax on the bark. Later, as they 

 grow, this scale becomes larger and changes color, being black, 

 gray or either of these colors, more or less mixed with white. 

 By the time the insect beneath has become adult, however, 

 the scale is quite uniformly gray or brown and about the 

 size of a pinhead. About a month is required for the in- 



