ORNAMENTAL PLANTS 469 



ance in the spring as small, orange-colored spots upon the 

 leaves and buds. These enlarge, and later become coated 

 with a light brown, dusty, fuzzy mold which destroys the 

 leaves and blossoms, often leaving only the naked stalks 

 standing. 



Sclerotia much hke those described under lettuce sclero- 

 tiniose appear in association with the decay in its late 

 stages. Their subsequent history is like that of lettuce 

 sclerotia. 



MIGNONETTE 



Cercosporose (Cercospora ResedxB Fckl.). — This disease 

 occasionally ruins the greenhouse crop. The spots are 

 at first minute, pale, with brownish or yellowish borders, or 

 they spread over the leaf as a reddish discoloration. Li 

 late stages they are uniform brown, with dark hyphae 

 scattered over the central portions. The dead areas 

 enlarge irregularly, and the leaves finally curl and die. 



Bordeaux mixture or ammoniacal copper carbonate, used 

 once a week, have proved effective remedies. 



NASTURTIUM 



Pseudomonose (Pseudomonas sp.). — In this disease the 

 leaves are ^\ilted and bear water-soaked spots 3-5 mm. 

 in diameter or larger. 



Alternariose (Alternaria oi Pleospora Tropceoli Halst.). — 

 The leaves which are affected turn light green, later 

 yellow, and still later are covered with a black mold. 



Damping ofif (CoUetotrichiim sp.). — Damping off due to 

 a species of colletotrichum is common in the cutting bed. 

 The diseased parts bear numerous black acervuli. 



