450 



BOARD OF AGRICULTURE. [Pub. Doc. 



Powdery Mildeio {Sphmrotheca pannosa, (Wallr.) Lev.), 



This occurs as a white, powdery mass on tlie upper sur- 

 face of the leaves, causing them to curl and become dis- 

 torted. The most skilled growers, however, succeed, as a 

 rule, in handling the conditions of the house so intelligently 

 that the mildew is prevented. In case it becomes trouble- 

 some, through lack of uncontrollable conditions, the standard 

 remedy to apply, and one which is very effectual, consists in 

 evaporating sulphur over a lamp. A more practical as well 

 as a more efficient method of applying sulphur is to repeat- 

 edly paint the pipes with a mixture of sulphur and oil. 



Black Spot [Actinonema Mosoe, (Lib.) Fr.). 



Black spot occurs on the leaves, causing them to turn 



more or less yellow, 

 f^f^ M and resulting in their 



falling off (see Fig. 9). 

 Certain spraying mix- 

 tures have been recom- 

 mended for black spot, 

 but the most satisfactory 

 method of treatment is 

 to keep the leaves picked 



FIG. 9. -Black spot of rose. ^ff^ ^j^^| ^^^^^^^ ^ ^.j^g^ 



atmosphere at night and on wet, dull days. 



Bronzing of Boses. 



Rose leaves frequently become spotted and turn yellow, 

 and drop off without being affected with the black spot fun- 

 gus. This happens to those leaves near where the stem has 

 been cut, and is a purely functional disorder, due, appar- 

 ently, to the starvation of that particular leaf. It resembles 

 somewhat the black spot, and is termed "bronzing." In 

 all probability it is a correlated growth phenomenon result- 

 ing from pruning. 



