TREES AND SHRUBS 



Plants which have been attacked the previous season should be sprayed 

 with a solution of potassium sulphide, or copper sulphate just before the 

 leaves expand. 



Hose Brand, Phragmidium mbcorticium, is the advanced stage of the 

 Kose Rust. It forms minute blackish projecting tufts on the under surface 

 of the leaves, taking the place of the gradually disappearing Rust in autumn. 

 Each point is a long and cylindrical teleutospore, of a very dark brown 

 colour, divided transversely into 3-7 cells. In the spring they produce 

 secondary spores which again give rise to the orange summer form. 



Preventive measures consist of collecting and burning all infected leaves, 

 not only those that are dead and fallen, but any that remain on bushes that 

 have been infected. 



Rose-leaf Rlack Blotch, Actinonema lioscv, is a common fungus, appearing 

 as somewhat rounded spots on the foliage, being at first purplish, and then 

 black. Radiating from the black spots are flexuous threads of a delicate 

 mycelium, and scattered among them are small black conceptacles contain- 

 ing sporules. The mycelium permeates the leaf tissues, causing premature 

 defoliation. 



Badly diseased leaves should be removed from the bushes and burned, 

 together with all diseased leaves lying on the ground. Spraying with potas- 

 sium sulphide, early in the season, and continued at intervals has been recom- 

 mended, but does not seem to have much effect when the disease has once 

 gained a foothold. Dilute copper sulphate, and Eau Celeste or Blue Water 

 are also used for spraying. 



Rose Leaf-spot or Leaf-scorch, Septoria Rosarwn, not only disfigures 

 the leaves, but seriously weakens the plant through premature defoliation, 

 badly diseased plants being often quite leafless by the end of July. The 

 fungus appears as rounded spots on the upper surface of the leaf, yellowish- 

 green at first, becoming pale brown later, and bordered by a dark purple 

 ring. The brown patches usually fall out, leaving holes in the leaf, but 

 they may remain fixed, and will sometimes be studded with minute black 



points, the perithecia or reproductive bodies of the fungus, containing thread- 



lxiv 





