New York Agricultural Experiment Station. 477 



injury being a discolored point or a tiny pit or depression surrounded 

 by a narrow ring of dead bark. (Plate XXX, figs. 1, 2.) If oviposition 

 were never attended with more serious consequences the work 

 of niveus in this respect could hardly be considered of enough impor- 

 tance to warrant it being listed as a pest of the apple. Such, unfor- 

 tunately, is not the case; for there is another form of injury which 

 apparently arises from a contamination of the wounds made in the 

 bark by the cricket by some infectious agent and appears as diseased 

 areas. These, in their external appearances and effects, resemble 

 superficially certain stages of the New York apple-tree canker 

 (S'phaeroTpsismalorum'Pk.) or the blight canker of apple trees (Bacillus 

 amylovorus (Burr.) de Toni). The affected spots range generally 

 from one-fourth of an inch to an inch in diameter, while the bark 

 within these limits varies from purplish or reddish-brown to pale 

 brown, depending apparently on the extent and age of the infection. 

 (Plate XXXII, figs. 1, 2.) Usually most of the diseased areas are 

 circular or somewhat oval in form, and occasionally one may observe 

 a large irregular extension of the original infected area as if there 

 had been a renewal of activities by the infectious agent. The bark 

 within the area of infection is generally slightly depressed and may 

 also be separated from the sound bark by a distinct line or narrow 

 crack. (Plate XXXI, fig. 2, and Plate XXXII, fig. 3.) In more 

 advanced stages cracks develop, separating the dead area from the 

 surrounding tissues, and there is formed a core which adheres loosely 

 to the wood (Plate XXXII, fig. 4), affording attractive situations 

 for the woolly aphis. (Plate XXXII, fig. 6.) From the wounds made 

 by the insect, located as a rule about the center of the diseased areas, 

 one may observe in April or May more or less flowing of a gummy, 

 reddish-colored liquid which on drying leaves a resinous product about 

 the orifices of the wounds. (Plate XXXII, fig. 1.) Not infrequently 

 there is an entire destruction of the bark which, on sloughing off, 

 leaves the underlying wood core exposed in spots of varying dimen- 

 sions. In some orchards such injuries occur to a serious extent. 

 These conditions may be quite generally observed on trees along 

 weedy roadsides or ravines or in apple orchards that are neglected or 

 are indifferently managed. Orchards that are given careful attention 

 are usually free from the trouble, although plantings — especially of 

 young apple trees growing near neglected orchards or near raspberry 

 plantations — have occasionally been observed which showed con- 



