76 HORTICULTURIST'S RULE-BOOK. 



rust, or mildew, which appears on the leaves, eventually 

 destroying the plants. 



Preventives. Start with perfectly healthy and vigorous 

 stock, and give good culture. In the house, endeavor to 

 avoid drafts, but give plenty of air on bright days. 



Remedies. Sulphide of potassium sprayed upon the 

 plants every few days. Bordeaux mixture. 

 Violet. VIOLET DISEASE or RUST (Cercospora Violce, Sacc., 

 and perhaps also Peronospora Violce, DeBary). Appears 

 on the leaves as small rounded light or brown spots, caus- 

 ing the leaf finally to wither and die. 



Preventives. It is supposed that any neglect or im- 

 proper handling renders the plants more liable to the 

 disease. Burn all infested plants, and do not use the same 

 soil again for violets. Sprays of copper compounds applied 

 during summer and fall. 



Watermelon. ANTHRACNOSE or POD-RUST. See under BEAN. 



BLIGHT, WILT, or WATERMELON DISEASE (Fusarium niveum, 



Smith) . Vines wilt suddenly and soon die, without 



apparent cause. The fungus occurs in the vessels of the 



stem. Serious in the South. 



Preventives. Rotation. Burn all diseased vines. Do 

 not throw the old vines on compost piles, for a common 

 source of infection is the manure spread upon the land. 

 POWDERY MILDEW. See under MUSKMELON. 



