PEACH DISEASES 321 



ward, being found in North Carolina, Virginia, West Virginia 

 and Arkansas. It also occurs, but rarely, in the state of Ohio. 

 The disease is not usually serious, although it prevails to a very 

 noticeable extent in damp, shaded localities on trees bearing 

 dense foliage. It was unusually prevalent on the Delaware 

 and Chesapeake peninsula in the fall of 1891. Pale, yellowish 

 or olivaceous spots with definite margins are produced by the 

 fungus Cercosporella Persicce on the upper surface of the leaves ; 

 on the lower surface, opposite the yellowish spots, will be 

 found a delicate frost-like growth of the fungus the conid- 

 iophores. 

 Little is known of the causal fungus and its control. 



REFERENCES 



Thaxter, R. Miscellaneous notes. Cercosporella Persicce Sacc. 



Connecticut Agr. Exp. Sta. Rept. 1889 : 173. 1890. 

 Smith, E. F. Field notes, 1891. Frosty mildew. Journ. Myc. 7: 



91-92. 1892. 



STEM-CANKER 



Caused by Phoma Persicce Sacc. 



In 1896 a peculiar stem-trouble was noted in Ohio affecting 

 primarily nursery-stock and the twigs of older orchard trees. 

 Two years later it was described, and was called constriction 

 disease, or stem-blight. It has subsequently been reported 

 from Connecticut and New York on seedling peaches. The 

 affected twigs are partially or completely girdled by a cankerous 

 formation. The parts above the lesion do not die immediately, 

 but eventually they succumb, as evidenced by a yellowing and 

 a premature defoliation. Just above the canker a swelling 

 of the stem occurs, resulting in a constricted appearance. Scat- 

 tered over the canker will be found numerous pycnidia of the 

 fungus which show as black specks. The pathogene develops 



