VEGETABLE AND FIELD CROPS 241 



by the usual characters of the powdery mildews. See grape. 

 If it should become troublesome, spraying with Bordeaux 

 mixture or ammoniacal copper carbonate must be prac- 

 ticed. 



Cylindrosporiose {Cylindrosporium Humuli Ell. & Ev.). 

 — Small, rusty brown, angular leaf spots largely limited 

 by the veins are present. They show most clearly upon 

 the lower sides of the leaves. Minute black acervuli are 

 present. 



The disease has been reported from several states, but 

 has not been regarded as serious. 



HORSE-RADISH 



Leaf blight, septoriose (Septoria Armoracice Sacc). — 

 Ruin is occasionally brought to a crop by this disease, 

 which is nearly always present to some extent. The leaves 

 bear numerous circular spots, blanched in the center and 

 pale yellow at their borders. Pycnidia are borne in the 

 centers of the spots. Badly affected leaves turn yellow 

 and become filled with holes caused by the dropping of the 

 dead tissue of the spots. 



Ramuiariose {Ramularia Armoracice Fckl.). — This spot 

 is much like the septoriose except that no pycnidia are 

 present. 



Black mold, macrosporiose (Macrosporium herculeum E. & 

 M.). — In late summer the leaf spots of this disease are 

 often abundant. They are circular, blanched, and later 

 coated with a black mold. The injury does not warrant 

 treatment. 



White rust (Albugo Candida (Pers.) Ktze.). — The dis- 

 ease is the same as that upon cabbage. It is often pres- 



