182 Report of the Botanist of Tns 



BLACKBERRY DISEASES. 



Canes Broken by Snow. — A good many blackberry canes were 

 broken by the heavy snow which fell about March 1, 1900; but the 

 loss from this cause was not nearly so great as fruit growers 

 feared it would be. 



Orange Rust {Pticoinia pcckiana Howe. Syn. Cwoma nitens 

 Schw.) — The blackberry rust so often mentioned in the economic 

 literature of plant diseases in this country is the orange rust, 

 Cwoma nitetis, which is believed to be the aecidial stage of Puccinia 

 pechiama. This is a common and destructive rust which is well 

 known to fruit growers. During the past year we have fre- 

 quently observed it on blackberries, sometimes doing much 

 damage. The reduction of prickles on rusted canes was found 

 to be less common than in the Hudson Valley. In Chautauqua 

 County at Ripley, Portland and Fredonia the rust was parasit- 

 ized by the fungus Tuherculina persicina (Ditm.) Succ. The 

 large dark-purple fruit bodies of the Tuberculina were abundant 

 on the under surface of the leaves. Where the parasite is pres- 

 ent the rusted plants are much less conspicuous because there is 

 less of the orange-colored powder. Spore production is greatly 

 checked by the parasite. 



Orange rust appears only in spring, runs its course and dis- 

 appears by July; hence it may be called spring rust. To be 

 sure, it has a fall form, the teleutospore form which is called 

 Puccinia pecJciana; but this is not common and moreover it is so 

 inconspicuous that it is rarely observed except by experts who 

 are searching for it. We have not observed it on blackberries 

 the past season. 



Yellow Fall Rust {Urcdo millleri Schroet.) — Besides the 

 orange rust above mentioned, mycologists recognize several 

 other rusts of blackberries; but, heretofore, only one other rust 

 has been reported as occurring in abundance on cultivated black- 

 berries. We refer to Chnjsomyxa albida Kiihn, which is called 

 white rust because of the pale yellow color of its spores. Stone 

 & Smith '° have reported the occurrence of white rust on culti- 



='" Stone, G. E. & Smith, R. E. Ninth Ann. Rep. Mass. (Hatch) Exp. Sta., 

 p. 74. 



