354 



FUNGOUS DISEASES OF PLANTS 



effuse colonies, the aerial portions of which are at first gray, be- 

 coming darker with age. The pycnidia may sometimes be pro- 

 duced in agar and also upon 

 various solid media in tube 

 cultures. 



Control. Preventive meas- 

 ures have not been carefully 

 worked out. Under ordinary 

 circumstances orchards in 

 good condition will suffer least. 

 Advantage may also be de- 

 rived from treating the limbs 

 and trunk thoroughly with any 

 " cleaning up " washes, or with 

 Bordeaux mixture. For varie- 

 ties susceptible to sunscald, 

 after which the canker may be 

 common, it is recommended to give a winter spraying with white- 

 wash. Pruning and scraping may also be required, and along with 

 this the wholesale destruction of affected limbs or fruit. 



Fig. 172. Isolation Culture of 



SpHyEROPS/S MALORUM 



XLVII. RASPBERRY CANE BLIGHT 



Coniothyrium Fuckelii Sacc. 



Stewart, F. C. Raspberry Cane Blight and Raspberry Yellows. N. Y. (Geneva) 

 Agl. Exp. Sta. Built. 226: 331-366. pis. 1-6. 1902. 



Habitat relations. This is a fungus which, as a disease-produc- 

 ing organism, has been known only a few years ; and it may be 

 that the species is new. The botanical name given above is applied 

 to a fungus which was described as occurring on a variety of shrubs 

 and trees, the genus Rubus being among the hosts mentioned. 

 Stewart and Eustace have tentatively referred the fungus caus- 

 ing raspberry cane blight to this variable species. 



The cane blight is a widespread disease in New York state, 

 and doubtless quite common throughout the country upon rasp- 

 berries. It is essentially a wilt disease (Fig. 173), and the principal 

 damage results to the fruiting canes. In some instances, however, 

 young canes may be killed during the first season of growth. 



