J. V. Eyrr and E. 8. Salmon 485 



of mildew on many of the leaves, were thoroughly sprayed with a 

 1-5 % solution. In this experiment the whole plants were treated, 

 including the youngest leaves and the growing tip of the stem, and each 

 leaf was sprayed on both surfaces. The injury produced by the third 

 day was very marked : many of the leaves were completely discoloured 

 and were more or less rigid, and dying or dead — at a touch they fell 

 to the ground — whereas others were only injured severely at the tip 

 and edges. The growing tips of two plants were killed. 



Taking into consideration also the effect produced by this material 

 on gooseberry foliage it seems clear that caustic soda by itself (or with 

 soap) is unhkely to prove a satisfactory fungicide, although the fact 

 that a 0-3 % solution exerts a partial fungicidal action must be taken 

 into account when considering the value of other substances exhibiting 

 alkaline properties. 



III. Ammonia. 



Hops. 1915. 



Exper. 1. Solution containing 0-5 % ammonia and 1 % soft soap. 



ist day. All the patches white and apparently only shghtly checked; the ba.ses 

 of the conidiophores everywhere visil)le. 



Uh day. The patches powdery or nearly so. 

 Gth day. All the patches powdery. 



Exper. 2. Solution containing 1 % ammonia and 1 % soft soap. 



\st day. The patches white, slightly checked ; bases of conidiophores everywhere 

 visible. 



■ith day. All the patches powdery or nearly so. 



(all day. All the patches as powdery as those on the "control" leaves. 



Exper. 3. Solution containing 1-5 % ammonia and 1 % soft soap. 



2nd dai/. The mildew little checked — some of the patches almost powdery. 

 Slight injury to the leaf in the form of minute, brown, "burnt" patches of cells — 

 one or two on each of the three sprayed leaves. 



8th dai/. All the patches now densely powdery; no further injury to the leaf. 



Exper. 4. Solution containing 2 % atmnonia and 1 % soft soap. 



2nd day. The mildew little checked, some of the patches almost powdery. Slight 

 injury to the leaf in the form of minute, brown, "burnt" patches of cells — two or 

 three on each of the three sprayed leaves; the tip of one leaf injured also. 



8th day. All the patches now densely powdery; no further injury to the leaf. 



