474 FuiKjiciilal Pritperlux, of Ccrtaiji Spratz-Fliiids 



carried out by one of us^ m 1913 ajipeared to tlirow considerable doubt 

 U2)oii the efficacy of this material as a spray. Moreover, the frequently- 

 observed scorching action on the foliage brouglit al)oiit by solutions 

 of "liver-of-sulphur"''-- make it desirable to find some material of fungi- 

 cidal value which is harmless to foliage and does not mark the berries. 



The wash recommended almost universally as efficacious against 

 the class of "powdery mildews"' {Eri/siphaceae) is a solution of '"liver- 

 of-sulphur''— generally understood to be a mixture of various sulphides 

 of potassium, although latterly the less valuable sodium carbonate 

 has replaced potassium carbonate in the preparation of "liver-of 

 sulphur" for horticultural purposes. An examination of the literature 

 on this subject, however, reveals the fact that definite information 

 is lacking on the two most essential points. (1) the strength at which 

 the solution is fungicidal; (2) the nature of the constituents of "liver- 

 of-sulphur" which are of fungicidal value. 



With regard to the strength at which a solution of "liver-of-sulphur" 

 is fungicidal we find a diversity of statement. English writers^ give 

 the proportion of 1 oz. to 2-3 gallons (English) of water; i.e. a 0-31 % 

 to 0-21 % solution; Sorauer* states that authors recommend a solution 

 containing from 0-25 % to 0-4 %. It may be mentioned that it is not 

 an uncommon practice among hop growers in this country when wishing 

 to combat hop-mildew to add from 1 to li lbs. of "liver-of-sulphur" 

 to the 100 gallons of "hop-wash," i.e. to use a 0-1% to 0-15% 

 solution of " liver-of-sulphur." American writers'" recommend for 

 use against mildews a solution containing I oz. to 2-4 gallons 

 (American) of water, i.e. from l)-37 % to 0-18 %8. Lodeman" states 

 that solutions containing from ()-19 % to 0-7.5 % of "liver-of-sulphur" 

 are used, without stating what concentrations are used against specific 

 diseases. Bourcart** mentions that Yesque recommends spraving with 



' Idem, loc. cit. p. 410. 



> Chittenden, F. J., in Jourti. R. Ilorl. Soc. xxxix. 373 (1914). 



» Ma.s8ee, G., Diseases of Cullimted Plants and Trees, p. .'iO (1910); Strawson, G. F , 

 fllandard Fungicides, p. 35 (1903). 



* Soraucr, P., Handbuch d. I'JIanzenhrankheilen, n. p. 525 (1908). 



« Duggar, B. M., Funrjmit: Diseases of Plants, p. 90 (1909); Stevens. V L. and Hal!, 

 J. G., Diseases of Economic Pldiils, p. 34 (1910). 



" It is probable (luit Knglisli copyi.sts have repeated the American formulae, oblivious 

 of tlie fact that tlie American gallon of water weighs only 8-34 lbs., and is therefore smaller 

 than the English gallon which weighs 10 lbs. 



' Lodeman, E. G., The Spraying of Plants, p. 103 (1903). 



' Bourcart, E., Insecticides, Fungicides, and Weedkillers, p. 115 (1913) (English 

 translation). 



