DISEASES AND INSECT PESTS 211 



and development has to be stolen from that manufac- 

 tured by other plants for their own use, hence fungi are 

 totally dependent on " host " plants, which they prey 

 upon and rob with detrimental results. 



Mildew. — The fungus which is most common and 

 does the greatest amount of damage in rose gardens 

 belongs to the Mildews, or the group of fungi known 

 scientifically as ErysiphecB. This Blight, or Mildew 

 {Sphoirotheca pannosa), is known to all gardeners who 

 are interested in roses. Its name. Mildew, or Meal-dew, 

 is ^derived from the characteristic appearance, and it 

 will be found parasitic upon the leaves and younger 

 growths of bushes, forming a fine, greyish-white, dust- 

 like cloud over all the affected parts. After the white 

 patches have been seen for a few days a distinct altera- 

 tion in the appearance of the foUage is noticeable ; the 

 parts attacked by the fungus become distorted ; leaves 

 curl up, twist, and assume a blistered appearance, while 

 the soft flower stalks, and, soon, the buds, swell to an 

 abnormal size and have a distorted, luihealthy look. A 

 lens will show the felted mass of mycelium covering the 

 fohage. Some varieties of the rose are more liable 

 to attack than others. 



Remedies. — Whenever the first signs of this fungus 

 are noticed, action must be taken immediately. For 

 light attacks fine sulphur or, better still, a mixture of 

 equal parts of fine quicklime and sulphur dusted on the 

 affected areas will soon check the disease ; it must be 

 brought into actual contact with the Mildew in order 

 to prove effective. On a small scale the sulphur may 



