60 THE PRESIDENT'S ADDRESS. 



In the mildews, however, the whole of the mycelium lies on 

 the surface of the part attacked, and is held in position by 

 numerous suckers or haustoria, which pierce the epidermal 

 cells of the leaf, where they play the double part of anchoring 

 the fungus to the leaf and absorbing food from its cells. 



The superficial nature of the mycelium enables the disease 

 to be readily combated if preventive measures are commenced 

 on the early appearance of the mildew. The remedy consists 

 in dusting the plants with powdered sulphur, mixed with 

 about one-quarter of its quantity of powdered quicklime. The 

 dredging should be done in the early morning when the foliage 

 is wet with dew. 



Strawberries often suffer severely from one of the mildews 

 {Sphaerotheca castaynei). The leaves are first attacked, and at 

 a later stage the fungus passes on to the fruit, which becomes 

 covered with a white bloom. Such diseased fruit is sometimes 

 dipped in water to remove the fungus and present a saleable 

 appearance, but the watery, insipid taste is sufficient to reveal 

 the deception practised. 



Such plants should be treated with powdered sulphur at 

 intervals of eight days until the fruit begins to set. In places 

 where the disease has existed the plants should be covered 

 with a thin layer of straw or other litter, and set fire to. By 

 this means all the old infected leaves, also fragments of diseased 

 leaves lying on the ground, are burned, and the plants afterwards 

 develop vigorous and healthy foliage. 



Another mildew, called Sphaerotheca pamiosa, proves very 

 destructive to roses, the leaves and young shoots becoming 

 covered with a white mould. Powdered sulphur, again, is a 

 remedy if applied at intervals after the earliest appearance of 

 the disease. Diseased leaves that have fallen should be collected 

 and burned, otherwise the fungus will mature its fruit on such 

 during the winter, and a fresh infection will follow the suc- 

 ceeding year. Diseased shoots should also be removed. 



