NEW YORK EXPERIMENT STATION BULLETIN 367 



were next to blocks of iiilesU'd applc-s, ilio iiidicaLions being that the 

 insects had come from the apjjles to the pears. The peach trees were 

 infested with the peach-tree borer. 



SPECIES OF INSECTS INCLUDED IN THIS llEPOKT. 



Only the more important species which are readily transferred on 

 nursery stock are included in this report. No account is taken of the 

 large number of species which attack the stock during the growing season 

 but which do not remain on the trees after the leaves are taken off and 

 hence are not readily scattered over the country by means of nursery 

 stock. 



For convenience the species herein discussed may be grouped under 

 four heads as follows: 



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



Scale Insects. 



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

 plum lecanium, the oak scale and the San Jos6 scale, 



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



sta uce Plant Lice, 



including the wooly aphis of the apple. 



III. Insects which bore into the tree Borers, 



including the i^each-tree borer. 



IV. Insects which feed on the buds and leaves and which hibernate 



on the twigs in protective cases Case-Bearers, 



including the pistol-case-bearer and the cigar-case-bearer. Although 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 which they can inflict, but because most species are very hard to 

 eradicate from a nursery or an orchard after the}^ have once become well 

 established. As a rule, however, scale insects need not become abundant 

 in the nursery if the stock is -carefulh' watched and the first few trees 

 found infested are either treated or burned. The most important species 

 found are discussed in detail as follows: 



THE OYSTER SHELL BARK- LOUSE. 



Mi/tila>ipiii pomorum Bouch6. 



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 iiijiny, especially in the 

 young orchard, and for this reason should be considered an important 

 pest in the nursery, even though the nursery trees themselves do not 

 usuallv become badlv infested. 



