FUNGI AFFECTING THE ROSE 



The Rose Mildew 



Spherotheca pannosa 



The mildew of roses is probably familiar to every 

 one who has grown these plants in a greenhouse. The 

 characteristic covering of mildew upon the leaves is very 

 likely to appear if the roses are neglected in any way. 

 Professor S. T. Maynard says that "^^'long experience in 

 growing the rose has led many to believe that the rose 

 mildew is brought on by various conditions that weaken 

 the vigor of the leaf, such as want of an abundance of 

 plant food in a proper condition^ unhealthy condition of 

 the soil^ often resulting from improper drainage, irregu- 

 lar or over-watering, or too sudden changes of tempera- 

 ture, especially after the plants have been forced at a 

 high temperature. The successful rose grower, there- 

 fore, is one who, by constant care and good judgment, 

 always provides against any or all of the above causes.'^ 



Treatment. — The ordinary method of preventing 

 the mildew is to close the house and fill it with sulphur 

 fumes three times a week. The sulphur may be put in 

 a thin iron kettle over a small kerosene stove, placed 

 where there is no danger of upsetting, and only fire 

 enough should be turned on to boil the sulphur. If it 

 catches fire the plants in the house might be ruined. 

 Probably spraying with copper carbonate solution, or 

 a similar fungicide, would also prove an effectual 

 preventive. 



11-4 



