J. Y. Eyre, E. S. Salmon and L. K. Wormald 301 



such commercial brands of lime-sulphur can safely be used at a much 

 greater dilution than at present, in which case no disfigurement of the 

 sprayed parts due to the dried deposit (such as is found at stronger 

 concentrations) would occur. 



Coiiiparison of Annitoiiiuiii polysulphide Soluiions X and XI 

 (both solutions with 1 % soap). 



Each solution was diluted to contain 0-078 % of polysulphide 

 sulphur. 



In Experiments lb, I'J, the two solutions behaved identically on 

 the leaves at the same nodes on the same plants, killing all the patches 

 on six leaves, and very nearly killing all the patches on the other six 

 leaves, the patches remaining alive producing only a few scattered 

 or clustered conidiophores at their edges. 



In E.xperiments 26, 27, practically the same results were obtained, 

 the mildew on each pair of leaves at the same mode being affected in 

 precisely the same manner. 



It is. obvious from these experiments (with 22 leaves, each bearing 

 numerous "powdery" patches) that both these solutions, with 0-078 % 

 2)olysulphide sulphur, were very nearly at fungicidal strength. 



Ammoniuni poh/sidphide Solnlion XI compared ivitJi this solution afler 

 precipitation of stdphiir (both solutions with 1% soap) (Table 4). 



In the first experiment (39, 10) with 13 leaves Solution XI, before 

 and after precipitation of sulphur, proved fungicidal; in the latter case 

 severe scorching injury resulted to the edges or tips of three leaves. 



In the second experiment 14 leaves were sprayed with 0-28 % 

 ammonium chloride (which was the amount present in Solution XI 

 after precipitation of its sulphur). Of the leaves opposite to these 14 

 leaves, seven (Nos. 1-7) were sprayed with 1 % Chiswick soap, in order 

 to see whether this substance had any fungicidal effect^ under the con- 

 ditions obtaining at the time of spraying; the remaining seven leaves 

 (Nos. 8-14) were sprayed with Solution XI after precipitation of its 

 sulphur. Owing to the material being poor, several leaves had ultimately 

 to be discarded. 



1 111 an experiment on May 18, I'JIS, three leaves (at the 7, 8 and 9 nodes) bearing 

 powdery patches were sprayed with 1 "„ Chiswick soft soap. On the next day only a few 

 of the patches showed le.ss than normal vigour, and by the third day all the patches were 

 as powdery as before spraying. 



Joum. of Agric. Sci. ix 20 



