496 Fungicidal Properties of Certain Sprcuj-Fluids 



Summary of Observations. V. 



Ill I'Jl-l proof was obtained that a solution of ammonium sulphide 

 containing 0-04 % sulphide-sulphur was powerful as a fungicide, while 

 solutions containing 0-06 %, (>08 % and 0-16 % sulphide-sulphur 

 proved uniformly efficacious in rendering the mildew permanently 

 sterile, and usually in reducing it by the 5th to 8th day to a dead or 

 dying condition. 



In 1915 solutions containing 0-02 %, 0-0:3 % and 0-04 % sulphide- 

 suljihur were found to be too weak to be a perfectly satisfactory fungi- 

 cide. When the concentration of sulphide-sulphur was 0-08 % the 

 solution was fungicidal in some cases, in others it was not quite so; 

 at 0-13 % the solution proved to bo invariably so. 



The above remarks apply to the effect of anuiioniuni sulphide 

 against Hop-mildew. In 1915 ammonimn sulphide containing 0-13 % 

 or 0-16 % sulphide-sulphur proved fungicidal against American Goose- 

 berry-mildew growing in the open, without causing any injury to the 

 leaves or tips of the shoots, or disfigurement to the berries. 



Patches of mildew treated with ammonium sulphide of a fungicidal 

 strength remain white and but little altered in appearance to the 

 superficial view, except that the mycelium may be in places more or 

 less collapsed and flocculent ; it remains persistently sterile until it passes 

 into a dying condition. In E.xper. 5, where a solution containing 

 0-08 % sulphide-sulphur was used on Hop-plants, the mildewed apex 

 of a shoot (with the mildew completely encircling the stem) was sprayed, 

 as well as the leaves bearing mildew. From the 1st day after spraying 

 to the I8th day (when the experiment was concluded) the mildew on 

 the upper leaves and on the stem remained white, although rendered 

 completely sterile by the fungicide. 



In Exper. 9, where a solution containing 0-13 % sulphide-sulphur 

 was used, Hop-leaves bearing mildew, and also the healthy ape.x of a 

 shoot and two healthy leaves, were sprayed on holh sides of the leaf 

 and iiU round the shoot', no injury resulted to the leaves or shoot. In 

 one experiment (No. 12) the solution containing O-Ui °/q sulphide- 

 sulphur caused serious injury to the Hop-leaves. 



The only instance we can find recorded of the use of ammonium 

 sulphide as a fungicide is that mentioned by Bourcart^ who states 

 that Dufour used it against Demalophora necatrix with negative results. 



' Bourcart, E., loc, cit. p. On. 



