In Eur()]K' the species first attracted attention by its occurrence on 

 young apple trees in 1884 ; in the United States it was noticed for the 

 first time in 1H77 through its injur}' to peach. Available data indicate 

 that plum is more susceptible to attack than other 

 trees, while peach, cherry, and apple are attacked 

 al)Out equally. Pear is also quite subject to infesta- 

 tion, and apricot, nectarine, quince, mountain ash, 

 and Juneberry trees also harbor this species. In 

 Europe mountain ash has been recorded by Dobner, 

 and hawthorn and elm by Eichhoff. 



Two important factors that have operated in the 

 past have had a marked effect in increasing the 

 numbers and consequent injury In' this as well as 

 other fruit-tree borers : ( 1 ) The introduction of other 

 destructive insects and diseases into many of the 

 districts which this insect inhal)its, which has un- 

 doul)tedly, l)y weakening the trees, afforded oppor- 

 tunities that would not otherwise have existed for 

 the multiplication of these borers; (2) severe wind- 

 tits nigviosvs in twig of storms that oftcu swccp through portions of the 



apple— natural size (an- • -i ^ • ^ ^ • i ± i.- 



thor-s illustration) Same region and which cause extensive destruction 



of fruit and other trees. The presence of the injured 

 and dying trees that are permitted to remain is a standing menance to 

 the culture of stone fruits, apples, and pears. 



One source of injury that is too often disregarded by the fruitgrower 

 is in permitting trees to remain after they are badly injured and useless 

 for any practical purpose except as firewood.^ 



Until recently there was a difference of opinion as to whether or not 

 this species was able to breed in vigorous trees, some writers going so 

 far as to assert that the beetles will attack only devitalized growth.^ 

 As a rule, only diseased trees or such as may already' be suffering from 



Fig. 2.-W(n-k of Sailii- 



' Dr. K. F. Smith, of this Department, has on several occasions noticed infested 

 orchards in the vicinity of wood yards or of brush or remnants of abandoned 

 orchards; three such instances are recorded by him (Bulletin 4, Division of 

 Vegetable Pathology, U. S. Dept. Agr., p. 30). In two cases cited, "peach 

 brush from diseased trees had been cut in the spring and piled near an orchard, 

 and in both the only attacked trees were in the vicinity of these piles, and those 

 most seriously attacked were nearest to them." 



-The writer and others have on several occasions seen peach trees that were 

 apparently free from disease and from insects other than the fruit-tree bark- 

 beetle. In one peach orchard, where the beetles were just commmencing attack 

 in September, nearly all the infested trees were, to every appearance, perfectly 

 healthj' ; in fact, one tree that looked feeble was scarcely at all affected, while a 

 neighboring tree that looked abosolutely sound was well covered with the beetk's 

 and their burrows. Mr. Peder Pedersen, who has carefully observed this species 

 in Montgomery County, Pa., has noticed a precisely similiar condition of affairs 

 at Huntingdon Valley, and INIr. W. P. Corsa, of the Division of Pomology, has 

 witnessed the same at Milford, Del., and Prof. E. A. Popenoe the same in Kan- 

 sas. See Bui, 19, n. s., Div. Knt., p. 96; also Lowe, Bui. 180, N. Y. Agl. 

 (Geneva) Kxp. Sta., i^p. 122-12S. 



