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 \vinter 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 

 SPXJEROPSIS 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. 



