294 Fungicidal Properties of Certain Spray-fluids 



covered over with densely powdery patches; on the tenth day there 

 were seven very small powdery patches. On leaf (e) there was no sign 

 of any living mildew on the fifth day, while the control leaf bore very 

 numerous powdery patches. On leaf (g) on the fifth day the only sign 

 of life was one small group of clustered conidiophores from one "hump," 

 the mildew in the other stages of development having been killed; 

 the control leaf was almost continuously covered with powdery patches. 

 By the tenth day four tiny tufts of conidiophores were observed coming 

 from the "humps." 



In Experiment 72 (1 : 50), on leaf {h) the mildew had reached the 

 stages of development characterised either by the presence of a minute 

 sterile patch of mycelium or by the presence only of scarcely observable 

 young mycelial hyphae radiating over the surface of the "hump"; 

 on leaf (c) there was no visible sign of infection beyond the presence of 

 green "humps"; on leaf (e) the mildew occurred either in the form of 

 tiny sterile mycelial patches or as "humps," while on leaf (g) only the 

 former stage was present. The solution proved fungicidal for all stages 

 of the mildew except the very earliest ones on leaf (c). On this leaf by the 

 fifth day there were a very few weak conidiophores from one infection 

 spot, while the control leaf bore numerous small powdery patches. On 

 the seventh day conidiophores to the number of 12 existed on the 

 sprayed leaf, and no further development had taken place by the tenth 

 day. 



Ammonium, polys idpkide Solution IV A (with 1 % soap). 



This solution diluted 1 : 1.50 exerted strong fungicidal powers. At 

 1 : 100 it was fungicidal for all "powdery" patches in one experiment, 

 and very nearly so in the second experiment. At 1 : 75 all "powdery" 

 patches were promj^tly killed, in many cases being almost completely 

 obliterated by the fifth day after spraying. At I : 50 the solution 

 proved, in two experiments, fungicidal for even the youngest stages 

 of development. 



Comparison of Ammonium polysulpliide Solutions VIII and XI 



(Table 2). 



These solutions tested^ at four strengths gave practically identical 

 results. 



With 0-010 % polysulphide sulphur the solutions were entirely 



' In these experiments, as in .all the following ones in whieh two solutions were compared 

 with each other, the leaves sprayed with the two solutions were always at the same node. 



