ORNAMENTAL PLANTS 455 



The course of the disease extends from a few days to several 

 weeks, or the disease may lie dormant for months, even 

 from season to season. Such cases of dormant disease 

 carry the infection to the succeeding crop and in commercial 

 corms from country to country. The rot spreads rapidly 

 from plant to plant by way of the diseased roots and through 

 the soil itself. The causal bacillus remains in the soil and 

 may attack healthy corms planted therein at later periods. 



No known treatment of diseased plants is practicable. 

 Infection of soil may be prevented by careful inspection of 

 all corms so as to avoid diseased ones. It is best to test 

 commercial corms in pots to be assured of their healthful- 

 ness before putting them in the beds. All soil from badly 

 infected beds should be disinfected or removed and fresh 

 soil supplied. 



Phyllostictose (Phyllostida Richardice) Halst.). — 

 Blighted leaves bear large ashen spots upon which are 

 numerous minute dark pycnidia. 



Cercosporose (Cercospora Richardicecola Atk.). — 

 This was first mentioned by Atkinson in 1891 as occurring 

 in Alabama. The edges of the leaves turn black in circular 

 spots. 



CARNATION 



Rust (Uromyces caryophyllinus (Schrk.) Schroet.). — 

 The carnation rust was first described in 1789 in Germany 

 and was noted in the United States by Arthur' in 1891, then 

 evidently a quite recent importation from the mother coun- 

 try. It rapidly became widespread through sale of infected 

 plants and cuttings and was soon present in almost all green- 



• Arthur, J. C, Bot. Gaz. 1891. 



