Plan t- Diseases. 



47 



Carnation. Rust (Septoria Dianthi. Desm.).— Attacks the leaves 

 in large, light brown spots, or occasionally the whole leaf 

 becomes discolored and wilts. Probably introduced from 

 Europe. 



Preventives. — If the disease is feared, be careful not to 

 apply water to the leaves. Ammoniacal carbonate of copper 

 or Bordeaux mixture. Burn all infested leaves. 



Another Rust (Uromyccs wryophyMinus, Schr.) also occurs 

 upon the carnation, producing gray blisters upon the leaves. 

 The treatment is the same as for the above. In both in- 

 stances, a careful picking and burning of the infected parts 

 is one of the surest preventives of further attacks. 

 Celery. Celekt-leaf Blight, Rust or Sux-Scald (Cei'cospora 

 Apii, Fries). — Appears in hot and dry places and seasons, 

 about mid-summer. Small yellowish spots appear upon the 

 leaves ; later the leaves turn yellow, then brown, and dies. 



Preventive. — Plant in a ino'ist and cool place, and shade the 

 plants if necessary. Destroy all diseased leaves in autumn. 

 Cherry. Bhowx-Rot (MonUia fructigena, Pers.). — Attacks flow- 

 ers, leaves and fruit. The flowers die and decay, the leaves 

 become discolored with brownish patches, and the fruit 

 rots on the tree. Attacks also peaches, plums and apples. 



Remedies. — Burn all infested fruit and leaves in the fall. 

 Before buds expand in spring spray with sulphate of iron 

 or copper. When the flowers are opening, spray again with 

 ammoniacal carbonate of copper, and repeat the operation at 

 intervals of a week or two until the fruit begins to color. 

 See under Peach. 

 Leaf-Rust. See under Plum. 

 Powdery Mildew. See under Apple. 

 Corn. Rot. — Due to bacteria. The plants are dwarfed, and 

 unusually slender. The roots become mucilaginous and 

 decay, as do the leaf-sheaths and the ears. 



No remedies or preventives are known except rotation. 

 Smut (Ustilago Zece-JIays, D. C). — A fungus attacking the ears 

 of corn, producing familiar black abnormal growths. 



Preventive. — Plant seed from clean fields. 



Remedies. — Cut out smut and burn it. Soak seed in sul- 

 phate of copper before planting. 

 Cottonwood. Leaf-Rust. — See under Poplar. 



