ORNAMENTAL PLANTS 



459 



length ; are elliptical in outline ; covered with a pinkish gray 

 mold ; irregularly dotted near the center with light yellow 

 spore masses. This is not common and may be 

 prevented by avoidance of the rust. 



Volutellose (Volutella Dianthi Atk.). — The 

 affected parts are pale and studded with mi- 

 nute black acervuli. This disease is of greatest 

 injury in the cutting bench. 



Heterosporiose, leaf mold {Heterosporium 

 echinulatum (Berk.) Cke.). — Circular spots, 1-4 

 mm. in diameter, bearing more or less concentric 

 zones of dark mold, appear upon the leaves, 

 especially the younger ones, also upon the stems 

 and sometimes upon the calyx. When upon the 

 calyx, deformation of the flower results. In some 

 instances the whole top of a plant becomes moldj'. 



Infected refuse and leaves should be burned and 

 Bordeaux mixture employed as a spray. 



Bacterial spot {Bacteria) . — The spots of the 

 leaves and stems are described by Woods' as 

 small, usually surrounded by a narrow water- 

 soaked area, while the center is commonly slightly 

 brown. As the spots grow larger they resemble 

 septoriose spots with the exception of the water- 

 soaked margin. Later they dry and collapse. 

 Badly diseased leaves wither. In some cases 

 nearly all the leaves on many of the stems are 

 so badly diseased as to be hopeless. 



This trouble can be checked by removing and burning 

 all diseased leaves, then spraying with formahn, 1 part to 



' Woods, A. F., Sci. n. s. 18. 537, October 23, 1903. 



Fig. 198.— 

 Carnation 

 fusariose 

 following 

 rust. Af- 

 ter Stew- 

 art. 



