DITISIOX OF HORTICULTURE 



641 



SESSIONAL PAPER No. 16 



injury from soluble sulphur. The risk in the case of the first two mixtures, however, 

 is light; in fact, the amount of injury here shown may be considered as the maxi- 

 mum, while in the case of soluble sulphur-arsenate the risk is beyond all question 

 and should not be taken. 



SOLUBLE SULPHUR. 



Although soluble sulphur has been on the market for some few years, it has not 

 as yet enjoyed the universal popularity, which perhaps such compounds will enjoy 

 in the near future. It has many points in its favour, such as being easy to mix, easy 

 to store and cheap to ship. The reason for the varied opinions and conflicting results 

 that have been obtained is due no doubt to the addition of the arsenate of lead. The 

 chemist tells us that soluble sulphur is largely sodium or potassium sulphide. This 

 being so, it is quite evident that upon the addition of lead arsenate there would be a 

 chemical reaction resulting in the formation of lead sulphate and consequently the 

 formation of either sodium or potassium arsenate. The latter are soluble, and if 

 soluble arsenate is present in any appreciable quantity serious foliage injury may be 

 expected. 



At the time of writing, experiments are under way in which arsenate of lime 

 is being used instead of lead arsenate. It is expected that this combination will solve 

 the difficulty and thus place these sulphide compounds within the reach of the average 

 grower. From the chemists' point of view, the combination of soluble sulphur and 

 arsenate of lime should not give injurious results, as there would not be any reaction 

 ■whereby soluble arsenates could be formed. It is hoped that by the end of another 

 season some definite data will be obtained on this question. 



Test of Soluble Sulphur, Bordeaux and Lime-Sulphur, Four Sprayings, May 7, June 



4, June 24, and July 7. 



How Treated. 



1. Soluble Sulphur 1 to 30, arsenate of lead l^b. to 40 gal. water 



2. Soluble Sulphur 1 to 40, arsenate of lead U lb. to 40 gal. water, 



3. Soluble Sulphur 1 to 40, no arsenate of lead 



4. Bordeaux, 4, 4, 40, 1^ arsenate of lead to 40 gal. water 



F0LI.\GE INJURY. 



Slightly 

 burned. 



% 

 47 

 471 



4^ 

 30 



Badly 

 burned. 



% 

 39^ 

 32 



Total 

 injury. 



% 



^ 

 30 

 (May 7 

 spray 

 omitted). 



How Treated. 



5. Bordeaux, 4, 4, 40, arsenate of lead H lb 



6 Bordeaux, 4, 4, 40, arsenate of lead 2 lb • 



7 Soluble Sulphur 1 to 30, arsenate of lead U lb. to 40 gal. water. 



8 Lime Sulphur 1 to 30, arsenate of lead U lb. to 40 gal water... . 



9 Lime Sulphur 1 to 40, arsenate of lead IJ lb. to 40 gal. water.. . 



10 Lime Sulphur 1 to 40, arsenate lead of 2 lb. to 40 gal. water. . . 



11 Solul^le Sulphur 1 to 40, arsenate of lead U lb- to 40 ga . water. 



12. Soluble Sulphur 1 to 40, arsenate of lead 2 lb. to 40 gal. water. 



13. Lime Sulphur 1 to 40, no arsenate of lead ,„ ; 



14. Soluble Sulphur 1 to 30, arsenate of lead 2 lb. to 40 gal. water 



Single Sprayings 

 for Foliage injury. 



Slightly 

 burned. 



% 

 23^ 

 24-2 

 39 



31-2 

 38-25 

 27 

 49 



52-75 

 31-5 

 42-5 



Badly 

 burned 



% 



29-7 



8-5 



12-25 



n 



12-75 

 27-5 

 2-75 

 47-5 



Total 

 injury. 



% 

 23| 

 31-7 

 68-7 

 39-7 

 50-5 

 28^ 

 61-75 

 80-25 

 34-25 

 90 



Ottawa. 



