442 Keport of the Entomologists of the 



I. Insects which secrete or otherwise produce a scale-like cov- 

 ering Scale Insects^ 



including the oyster-shell bark-louse, scurfy bark-louse, the New 

 York plum lecanium, the oak scale and the San Jost? scale. 



II. Insects which secrete honey dew or a bluish-whie flocculent 



substance Plant Lice, 



including the w^oolly aphis of the apple. 



III. Insects which bore into the trees Borers, 



including the peach-tree borer. 



IV. Insects which feed on the buds and leaves and which hiber- 

 nate on the twigs in protective cases Case-Bearers, 



including the pistol-case-bearer and the cigar-case-bearer. Al- 

 though not a true case-bearing insect the bud moth may for 

 convenience be included under this head. 



SCALE INSECTS. 



Scale insects are among the most common of the insect pests. 

 The group includes a large number of species. As destructive 

 insects they rank among the first and are to be dreaded, not only 

 because of the great injury w^hich they can inflict, but because 

 most species are very hard to eradicate from a nursery or an 

 orchard after they have once become well established. As a ruh?, 

 however, scale insects need not become abundant in the nursery 

 if the stock is carefully watched and the first few trees found 

 infested are either treated or burned. The most important spe- 

 cies found are discussed in detail as follows: 



The Oyster Shell Bark Louse. 

 Mytilaspis pomorum Bouch^. 

 This insect is so commonly found in the orchard that it is liable 

 to be considered of little importance. It is less harmful than 

 many other scale insects yet it is capable of doing very serious 

 injury, especially in the young orchard, and for this reason 

 ehonld be considered an important pest in the nursery, even 

 though the nursery trees themselves do not usually become badly 

 infested). 



