15 



In the case of rust and black spot, the winter spores, or 

 those spores that start the disease the following season, 

 are produced on the leaves. Those infected leaves 

 mostly fall to the ground in due course, and many such 

 are blown into nooks and crannies, where they remain 

 until the following spring, when the winter spores they 

 bear produce other still smaller spores, which are 

 dispersed by wind, &c., and renew the disease. The 

 remedy consists in collecting and burning all fallen 

 leaves, also those that remain on infected bushes. 



Notwithstanding all possible precautions being taken 

 on the lines indicated, you may rest assured that some 

 winter spores have escaped detection, or have been 

 transported by wind, birds, &c., from some neighbours* 

 garden where no preventive measures have been 

 exercised ; or, finally, from wild Roses growing in the 

 neighbourhood. 



To meet this probability, or better say certainty, 

 spraying is absolutely necessary. It is important to 

 grasp the fact that spraying is purely preventive in its 

 action. No disease can be cured by spraying ! If a 

 mildewed Rose tree is sprayed the leaves that are already 

 diseased are not cured, but the disease may sometimes 

 be prevented from extending, owing to the substance 

 deposited on the leaves acting as a poison, and killing 

 those spores that alight on the leaves, which would 

 otherwise set up a new point of infection. From the 

 above account it will be seen that spraying is of value 

 in proportion to the time the substance sprayed remains 

 on the plant. Unfortunately the most effective spraying 

 solution, and the one that remains for the longest period 



B 



