THE PLUMS OF NEW YORK. 133 



& Robinson) attacks the plum and in New York has been found particu- 

 larly injurious to the Wickson plums. The flat -headed apple tree borer l 

 (Chrysobothris femorata Fabricius) is frequently found in the wood of 

 wild plums and is sometimes a pest of the several cultivated species. It 

 is treated as is the peach borer. The shot -hole borer ' (Eccoptogaster rugu- 

 losus Ratzeburg) a diminutive insect which deposits its eggs in the trunks or 

 large branches of various members of the genus Prunus, may be regarded 

 as an effect rather than a cause of disease, for it seldom injures perfectly 

 healthy plum trees. The peach bark-beetle ' (Phlceotribus liminaris 

 Harris) is somewhat similar in its work to the shot -hole borer and like 

 it is found for most part only in diseased and decrepit trees. 



The plum aphis * (Aphis prunifolii Fitch) is sometimes very destruc- 

 tive to varieties of the native plums, especially the Americanas, and occa- 

 sionally injures or even kills the young trees of the Domestica sorts. It 

 is not a formidable foe in New York, and it is the exception when trees 

 must be treated for it, the treatment being any of the contact solutions 

 used against sucking insects. The cherry aphis ' (Myzus cerasi Linnaeus) 

 and the green peach aphis ' (My::.us persicce Sulzer) are much less common 

 than the plum aphis on plum trees, but are sometimes abundant on foliage 

 of this fruit and are combated in the same way as the more common aphis. 

 Gillette enumerates two other aphids as attacking the plum in Colorado 

 the rusty brown plum louse ' (Aphis setaria Thomas) and the mealy 

 plum louse ' (Hyalopterus arundinis Fabricius). 



Several scale insects infest the plum. Chief of these is the dreaded 

 San Jose scale ' (Aspidiotus perniciosus Comstock) known and feared 

 by all fruit-growers in the United States. The lime and sulphur solution 

 is now the most common and probably the most effective spray for this 

 insect. The European fruit lecanium '" (Lecanium corni Bouche) occa- 

 sionally does a great deal of damage in New York and now and then de- 

 stroys the whole crop in an orchard. The winter treatment for San Jose" 



1 Riley, C. V. An. Rpt. Slate Entomol. Mo. 1:46-47. 1869. 



'Lowe, V. H. AT. Y. Sta. Bui. 180:122-128. 1900. 



'Wilson, H. P. The Peach-tree Barkbeetle U. S. D. A. Bur. Ent. Bui. 68:91-108. 1909. 



4 Hunter, W. D. The Aphidids of N. A. la. Sta. Bui. 60:103. 1901. 



'Ibid. 107, 108. 



* Ibid. 108, 109. 



7 Gillette, C. P. A Few Orchard Plant Lice Col. Sta. Bui. 133:41- 1908. 



'Ibid: 39, 



9 Marlatt, C. L. The San Jose or Chinese Scale U. S. D. A. Bur. Ent. Bui. 62:1-89. 1906. 



10 Lowe, V. H. The New York Plum Lecanium N. Y. Sta. Bui. 136.583. 1897. 



