ROSE DISEASES. 247 



the house full of sulphur, let the house remam closed until 

 it reaches 85 to 90 deg., then admit air gradually. A 

 constant circulation of air is likewise recommended for 

 roses at all times. 



Remedies. — Potassium sulphide one ounce to five gal- 

 lons of rain water sprayed upon the plants has proved 

 an effective remedy. Spraying in winter, too, with the 

 Cupram Formula (No. 25) would prove a good preventive 

 remedy. Rosarians, from long experience, have come to 

 the belief that rose mildew is induced by a weak condi- 

 tion of the plant, resulting from partial starvation, irregu- 

 lar or excessive watering, and undue exposure to draughts 

 of cold air. The best successes in rose growing, as in 

 other things, attend those who give constant intelligent 

 care to the many details. 



Rose Leaf Scorch (Septoria rosoe). — This disease is 

 caused by a fungus which manifests itself first in the 

 form of yellowish patches, which eventually change to a 

 - brownish tint, margined by a darker tint. The mycelium 

 penetrates the cells, stops the circulation of the sap, and 

 causes the affected portions to die and fall out, leaving 

 holes in the leaves. As this fungus is common on wild 

 roses and brambles, it readily finds its way on to garden 

 roses. 



Remedies. — Spraying the trees in winter with a sulphate 

 of copper solution (Formula No. 26) will kill the winter 

 form of the fungus, and an occasional spraying with sul- 

 phide of potassium in spring and summer will keep the 

 trees free of this pest. 



Rose Rust (Phragmidium subcorticatum). — The genu- 

 ine rust of the rose, similar to the rust of wheat, oats, and 

 other grasses, is not common in this country upon indoor 

 roses. It is not unlikely that it may become a pest here 

 as it now is in California and other States in the Union. 

 Those who are familiar with the rust of the blackberry 

 need no further words of general description of this fungus. 



