THKEE COMMON ORCHARD SCALES. 



BY DK. H. T. FERNAL1), PROFESSOR OF ENTOMOLOGY, MASSACHUSETTS 



AGRICULTURAL COLLEGE. 



Our knowledge of scale insects has been very limited 

 until recently. The injuries they cause have passed un- 

 noticed in most cases, while the occasional loss of some tree 

 has too often been attributed to some other cause. The 

 appearance of the San Jose scale in Massachusetts, how- 

 ever, and its rapid extension over the State, followed 

 everywhere by serious injury to the trees attacked, has 

 attracted much attention to this group of insects. 



Although over a hundred different kinds of scale insects 

 probably occur in Massachusetts, only three are likely to 

 be present in any orchard in sufficient abundance to cause 

 injury to the trees and demand attention, and only one of 

 these is usually so destructive as to require radical measures 

 for its control. These three are the oyster-shell scale, the 

 scurfy scale and the San Jose scale. It is important that 

 every person having fruit trees should learn to recognize 

 these three scales, and know what treatment to apply for 

 each if he wishes to obtain his crops, or, in case of the San 

 Jose scale, if he wishes even to keep his trees alive. 



The Oyster-shell Scale. 

 (Mytilasjris pomorum Bouche.) 

 This scale is a native of Europe, and reached this coun- 

 try, where it is now generally distributed, about a hundred 

 years ago. It is probably present in every orchard in 

 Massachusetts in greater or less numbers, and is also abun- 

 dant on many of our shade and forest trees. 



During the winter the scales of this insect are very notice- 

 able on the twigs and smaller branches of many trees, often 



