106 



SEVENTEENTH REPORT. 



BARIUM POLYSULFIDB TESTS. 



l-,*iO dilution. 



This dilution was made bv takin<»' 1 <;]n. of llie nuiterial aiicl 

 allowing- it to dissolve in 30 ec. of cold water. 



TABLE XII.— FUNGICIDAL VALUE OF 1-30 BARIUM POLYSULFIDE. 



Average germination of spores in this test was 77%, which is 

 somewhat higher than that which would represent a valuable fungi- 

 cidal action. Judging b}" the action of other sulfur fungicides on 

 cucumbers it is unlikeh- that this could be used successfully on 

 such tender plants in this dilution. 



However, even were it i)ossible to use the compound, none of 

 the dilutions used gave any indications that it would be of value in 

 controlling the fungus attack. To be effective against so severe an 

 organism as this has been proven to be, it would be necessar}^ to 

 have some fungicide which practically i)rohibits germination, as 

 Bordeaux mixture seems to do. 



TEST WITH POTASSIUM SULFIDE. 



This was used in a dilution corresponding to a common formula 

 which is as follows : — 



3 ounces of KjS. 

 10 gallons of water. 



This is equivalent to a mixture made with 1 gm. of K._,S and 427 

 cc. of water and the dilution was prepared by this formula from 

 chemically pure KoS. 



