INSECT, DISEASES AND SPRAYING 57 



sulphur, by means of it, is boiled in a kettle 

 for two or three hours twice a week, the house 

 being closed during the operation. The only 

 precaution is to use no more heat than is 

 sufficient to boil the sulphur, for should it 

 catch fire it might damage the plants. Mr. 

 John N. May writes that the best way to get 

 rid of the mildew on roses under glass is to 

 close the house about eight o'clock in the 

 morning, run the temperature up to 75, 

 then, with a bellows, fill the house full of 

 sulphur. Let the house remain closed till it 

 reaches 85 or 90, and afterward let air in 

 gradually. A constant circulation of air is 

 likewise recommended for roses at all times. 

 Potassium sulphide, one ounce to two gallons 

 of water, sprayed upon the plants has proved 

 an effective remedy. Dr. Massee states that 

 "flowers of sulphur mixed with about one- 

 third of its volume of slaked lime dusted on 

 the foliage prevents the spread of the disease." 

 Gardeners, from long experience, have come 

 to the belief that rose mildew is induced by 

 a weak condition of the plant, resulting from 

 partial starvation, irregular or excessive water- 

 ing, and undue exposure to drafts of cold air. 

 The best success in rose growing, as in all 



