Calceolaria Diseases 215 



Calceolaria (^Calceolaria arachnoidea') 



Cultural Considerations. Calceolariae are green- 

 house annuals grown for decorative purposes. It 

 requires a soil made of equal parts of leaf mold, 

 sand, and sand loam. The plants require frequent 

 repotting to prevent them from becoming potbound, 

 although the flowers are usually better when pot- 

 bound. The plants require a northern exposure dur- 

 ing the summer, plenty of ventilation, and a cool 

 house. A temperature of 70 degrees F. may seri- 

 ously injure them. Partial shading should be pro- 

 vided, and no water should be permitted to accu- 

 mulate on the foliage. 



Diseases of the Calceolaria 



The Calceolaria is apparently a very resistant 

 plant. Halsted,* however, records a leaf blight that 

 affects it. The trouble appears as brownish patches 

 on the leaves just about blossoming time. The 

 patches are many sided and seem to be bound by 

 the smaller veins of the leaf (fig. 44). The spots 

 are water-soaked, and transparent when held against 

 any light. The cause of this trouble seems to be a 

 bacterial organism which, however, needs further in- 

 vestigation. The same is true for methods of con- 

 trol. 



• Halsted, B. D., New Jersey Agr. Expt. Sta, 14th Ann. Kept.: 

 430-431, 1893. 



