THE FLTNGTCIDAL PROPERTIES OF CERTAIN 

 SPRAY-FLUIDS. 



By J. VARGAS EYRE anh E. 8. 8ALM0N. 

 (Research Depart merit, South-Eastern Agricultural College, Wye, Kent.) 



Introductory. 



The object of the experiments described below was to establish 

 more clearly to what the fungicidal value of alkahne sulphide solutions 

 is to be attributed. 



For tills purpose a study was made during 1914 and 1915 of the 

 fungicidal action of certain chemicals, principally sulphides, on species 

 of the "powdery mildews" {Erysiphaceae) under as exact conditions 

 as possible. Information, based on carefully controlled experiments 

 with actively-growing patches of the mildew, appears to be entirely 

 lacking, notwithstanding the large amount of attention which has 

 been given to the subject. 



The economic importance of combating these mildews is very 

 considerable. To take one instance — that of the American Gooseberry- 

 mildew — it has to be recognised that the continuance of the commercial 

 cultivation of this fruit depends upon a satisfactory spray being found. 

 In this connection the lime-sulphur wash has proved, under practical 

 conditions^, of great value in protecting the gooseberry bush from early 

 attacks of the mildew, but the strongly-adherent deposit produced 

 by this wash renders its use objectionable for later sprayings on account 

 of the disfigurement caused to the berries^. A solution of "liver-of- 

 sulphur" leaves no visible deposit and has been commonly recommended 

 against the American Gooseberry-mildew, but certain experiments 



1 Salmon, E. S., in Jnurn. Soulh-Easiern Agric. Coll. xxn. 403 (1913) [1914]. 

 - Idem, he. cit. p. 423. 



