ORNAMENTAL PLANTS 461 



Rhizoctoniose, Stem rot {Rhizodonia sp.). — The plants 

 suddenly wilt, dry, and die, while the outer portion of 

 the stem becomes soft and rotten. Sclerotia as described 

 for the potato are present. For further discussion of stem 

 rot, see p. 61. 



CHRYSANTHEMUM 



Septoriose, leaf spot (Septoria chrysanthemi Allesch.). — 

 Large brown to black blotches, often irregularly circular 

 and of indefinite border, appear upon the leaves. These 

 enlarge and coalesce to involve the whole leaf, which 

 withers, dies, and falls away. 



The lower leaves are first affected, but in later stages all 

 the leaves of the plant may be badly spotted, and practically 

 complete defoliation may result. Cuttings from infected 

 stock should be avoided. All diseased fohage should be 

 picked, collected, and burned, and the remaining fohage 

 should be sprayed with Bordeaux mixture with soap added 

 sufficient to form a suds to increase its adhesive power. 

 Five or six sprays during the season are usually sufficient.' 



Phyllostictose (Phillostida sp.). — This disease, first de- 

 scribed in 1893, is very similar to the above, except that 

 the spots are more regularly circular, are purpUsh brown, 

 and with a distinct border. Pycnidia which may often 

 be seen with the naked eye are present. 



Rust (Puccinia chrysanthemi Roze). — Apparently a 

 native of Japan, the rust was introduced into England 

 (1895) and Europe through commercial agencies,^ and 

 similarly into the United States, where it was first noted 



> Beach, S. A., N.Y. (Geneva) Agr. Exp. Sta. Rpt. 1892, p. 5.57. 

 ' Arthur, J. C, Ind. Agr. Exp. Sta. Bui. 85, p. 150, October, 1900. 



