SODA BORDEAUX (BURGUNDY MIXTURE) 



FRANK T. SHUTT, M. A., CHE;M 1ST, EXPERIMENTAL FARMS. 



DURING July a number of reports were 

 received, both from Ontario and 

 Nova Scotia, stating that serious injury has 

 resulted from the use of Soda-Bordeaux on 

 apples, plums, cherries and peaches. These 

 communications have been accompanied 

 by requests for information respecting this 

 newly-introduced mixture. A brief ac- 

 count of certain experiments recently con- 

 ducted at the Experimental Farm, Ottawa, 

 may, therefore, be of value and interest to 

 fruit growers generally. 



In Soda-Bordeaux, or Burgundy mix- 

 ture (suggested as an alternative for the 

 ordinary Bordeaux mixture for potato 

 blight and rot), washing soda (carbonate of 

 soda) is substituted for lime in the prepa- 

 ration of the spray. Two formulae have 

 been recommended : 



Copper sulphate (bluestone) . . 6 lbs. 

 Washing soda (carbonate of 



soda). . 71/2 lbs. 



Water 40 gals. 



B. 



4 lbs. 



5 lbs. 

 40 gals 



A simple calculation will show that the 

 proportion of bluestone to washing soda is 

 the same in each, but " B " is a more dilute 

 preparation. 



As far as the writer can learn, paris 

 green, white arsenic, or some other arseni- 

 cal compound, had been added to the Soda- 

 Bordeaux in every case in which injury was 

 reported from application to fruit trees. 

 When paris green is mixed with ordinary 

 Bordeaux mixture it is not dissolved, but 

 remains in suspension, and experience has 

 shown that no injury results from the use 

 of such a spray. When, however, paris 

 green is added to Burgundy mixture it is 

 partly dissolved, owing to the alkaline com- 

 pound more or less corrosive to foliage. It 

 has long been known that soluble arsenical 

 compounds have this injurious effect upon 

 foliage, and consequently cannot be used in 

 insecticidal mixtures. It follows from this 

 consideration that the addition to the Bur- 

 gundy mixture of a solution made by boil- 

 ing white arsenic and sal soda (resulting in 

 the formation of arsenite of soda), as prac- 

 ticed by some, would render the spray ex- 

 tremely injurious. For these reasons it 

 might well be conjectured that the addition 

 of paris green or arsenic in any form to the 

 Burgundy mixture would render it unsafe 

 for use on fruit trees. 



One of the Fruit Farms For Which British Columbia 4s Becoming Famous. 



The Richter oi chard and farm at Keremeos, Similkamean, British Columbia, is here shown in part. The light 

 background is the steep side of a high mountain. On this farm the alfalfa fields yield four crops annually. Apricots, 

 peaches, almonds and grapes, including Black Hamburg, reach perfection. 



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