DISEASES AND INSECT PESTS 213 



must be exercised to see that the best cultural methods 

 possible are practised. 



Fresh plants brought into the garden may cause a 

 renewal of the disease, and in a humid, warm season it 

 spreads with startling rapidity. Whenever new bushes 

 arrive from the nursery they ought, therefore, to be 

 sprayed with the fungicide as a prevention against the 

 introduction of any fungoid disease. 



Rust. — A rust called Phragmidium mucronatum 

 attacks rose bushes in some localities. This fungus 

 appears in two forms ; The summer condition, at one 

 time known as Rose Rust, or Uredo, shows as a pale 

 yellow dust which, when examined microscopically, is 

 seen to consist of roundish, prickly bodies. The autumn 

 state, known poptilarly as Rose Brand, is formed of rows 

 of cells having a brown appearance, and still bearing 

 the tiny, warty, prickly growths. Both forms appear on 

 the under sides of the leaves in scattered colonies ; it 

 is not so destructive as the Mildew. 



Remedies. — As soon as the rust is noticed, pick off 

 all infested leaves and burn them. Sulphur has slow 

 effect on this fungus, but Bordeaux mixture sprayed 

 from below removes it from the bushes. 



Rose Leaf Blotch or Black Spot. — ^This fungus is 

 becoming more widely distributed. It is not, by some, 

 considered a destructive pest, but as it weakens the 

 bush by preventing the foliage from performing its work 

 of digesting the plant foods absorbed through the roots, 

 and by causing premature defoUation, some means of 

 eradication should be adopted. The foliage of a fine rose 



