92 THE BOOK OF ROSES 



this crop of fungus that the winter spores are produced 

 which infect the plants in the following Spring. Spray- 

 ing should be done frequently throughout the danger 

 periods, and a good solution for this purpose, recom- 

 mended by Mr Massee, is one part of commercial 

 sulphuric acid diluted with one thousand parts of water. 

 This must not be used full strength unless it is quite 

 certain that the foliage is hard and ripe, and in any case 

 it is well to begin with a weaker solution, strengthening 

 it when necessary later. This is not very adhesive, 

 owing to the large proportion of water it contains, and 

 needs frequent renewal. It must be mixed in a wooden 

 pail or tub, as the acid will corrode metal, and after 

 using it a little pure water should be run through the 

 syringe or sprayer to remove any acid. The finer the 

 spray employed the better, as it will not so quickly run 

 off the foliage. 



Dusting the whole plant with flowers of sulphur by 

 means of a fine muslin bag is a good means of checking 

 the mildew, where for any reason spraying is impossible, 

 and this should be done on a calm fine evening as soon 

 as the mildew is observed, repeating it at intervals until 

 no trace of the fungus can be seen. 



Rose rust is another of the pests of the Rose garden, 

 though by no means as common as mildew. It appears 

 as an orange-coloured spot on the leaves, hence its other 

 name of orange fungus. It affects the wood also, and 

 when the patch is large and neglected sometimes causes 

 curvature of the stem at the affected place. When the 

 fungus dies away in the winter it leaves large wounds in 

 the wood, which serve as harbourage for other sorts of 

 fungi. The winter spores are produced on the leaves, 

 so that it is most important in cases of this disease that 

 all affected leaves should be collected when they fall, 

 gathered into a heap and burnt. Rose trees that have 

 been affected with rust should, in the following Spring, 



