J. V. Eyre, E. S. Salmon and L. K. Wormald 291 



patches had befiiin to produce fresh conidiophores. By the ninth day 

 it was evident that some of the patches on the lower leaf were dead, 

 and from the remaining patches only a few weak conidiophores had 

 been produced; on the upper leaf all the eight patches had densely 

 clustered conidiophores and were again powdery. 



Again, in Experiment 91, with the solution at the same strength, 

 the powdery patches on the two leaves of one plant, at the sixth and 

 fifth nodes from the apex, showed different powers of resistance. On 

 the fifth day after spraying, the patches on the lower leaf were sterile 

 or partly obliterated, while the control leaf was densely powdery; the 

 patches on the upper leaf had regrown conidiophores and were now 

 almost as powdery as those of the "control" leaf. By the tenth day 

 some of the patches on the lower leaf were dead, but a few patches had 

 revived and produced conidiophores and were now sub-powdery; on the 

 upper leaf ail the original patches were now densely powdery like those 

 of the "control" leaf. 



Ammonium polysulfhide Solution 111 (with 1 % soap). 



This solution diluted 1:100 has considerable fungicidal powers. 

 At 1 : 50 it was completely fungicidal in one experiment, and very 

 nearly fungicidal in two experiments. It was fungicidal at 1 : 30 in the 

 one experiment at this strength, and caused slight but distinct injury 

 to six of the eight leaves sprayed. 



In Experiment 79, with the solution diluted 1 : 100, there was 

 clear evidence showing that the reaction of the mildew to the solution 

 varied according to the different stages of growth reached by the fungus. 

 On one of the plants used three leaves were sprayed; leaf {a) at the fifth 

 node from the ape.x bore numerous powdery patches, leaf (6) at the fourth 

 node also bore numerous powdery patches, while leaf (c) at the third 

 node bore very young mycelial patches without conidiophores. On the 

 eleventh day after spraying, the patches on leaf (a) were dead, while the 

 control leaf bore powdery patches; on leaf (6) a few patches were dead, 

 some patches had newly produced a few scattered conidiophores either 

 at the centre of the patch or at its periphery, but most patches had 

 produced clustered conidiophores again over most of their surface and 

 were again powdery or sub-powdery — the mildew-patches on the control 

 being only slightly more vigorous; on leaf c there w^ere numerous very 

 powdery patches, — the solution not having stopped the development 

 of the young stage, there was no difference between the sprayed leaf 

 and the control leaf. 



