286 



DISEASES OF ECONOMIC PLANTS 



ROSELLE (Hibiscus Sabdariffa) 



Powdery mildew (Microsphcera Euphorhice B. & C.)- — 

 This mildew of characteristic white, flower- 

 like, circular patches has been noted in 

 Florida. 



Flowers of sulphur have proved effective 

 in preventing its spread, according to Bessey 

 as cited by Fawcett.^ 



Fig. 124. — White 

 rust (albugese) 

 upon salsify 

 leaves. After 

 Heald. 



SALSIFY 



White rust (Albugo Tragopogonis (DC.) 

 Gray). — White, rustlike, bUsters (sori) 

 upon the leaf indicate this disease. The 

 sori are longer than broad, extending 

 lengthwise of the leaf. In late stages of 

 the disease the leaf near the sori blackens 

 and withers, often tearing lengthwise. 



Bacteriose. — A soft rot of the roots, re- 

 sulting in loss of green color and prostra- 

 tion of the plants, is attributed to bacteria.- 

 The slimy, offensive decay usually begins 

 at the lower end of the main root and 

 progresses upward. See carrot soft rot. 



Rust (Pucdnia Tragopogonis (Pers.) 

 Cda.). — This true rust is of somewhat 

 general distribution, but is not harmful. 



SPINACH 

 Anthracnose (Colletotri churn Spinacece Ell. & Halst.). — 



1 Fawcett, H. S., Fla. Agr. Exp. Sta. Rpt. 88. 



2 Halsted, B. D., N.J. Agr. Exp. Sta. Rpt. ii, 351, 1890. 



