EXPERIMENTS WITH FUNGICIDES ON POTATOES 



IN 1900. 



Chas. D. Woods. 



As noted in Bulletin 68 of the Station, a spraying experiment 

 with Bordeaux mixture as a preventative of potato blight was 

 successfully carried out on a farm of Mr. John Watson in Houl- 

 ton. Mr. Watson placed the whole of the potato fields on his 

 farm, and the services of his farm laborers at the disposal of 

 the Station. The experiment was planned partly as a dem- 

 onstration of the value of Bordeaux mixture when applied on a 

 large scale, and partly as a comparison between freshly pre- 

 pared Bordeaux mixture and the ready prepared goods on the 

 market. 



THE FUNGICIDES USED. 



The Bordeaux mixture was prepared according to the fol- 

 lowing formula. 



Copper sulphate 5 pounds 



Fresh lime (unslaked) 5 pounds. 



Water 50 gallons 



A single barrel can be readily prepared as follows : 

 The copper salt is dissolved in a wooden tub or earthen jar 

 arid the lime slaked in a separate vessel. Dissolve the copper 

 sulphate in about two gallons of hot water in a wooden or 

 earthen vessel by stirring, or by suspending it from the top of 

 the vessel in a cloth bag, immersed in the water ; pour the solu- 

 tion into the tank or barrel used for spraying and fill one-third 

 to one-half full of water. Slake the lime in a separate vessel 

 by the addition of a small quantity o>f water, and when slaked 

 add two or three gallons of water and stir freely. Pour the 

 milk of lime thus made into the copper sulphate solution, pass- 

 ing it through a brass wire strainer of about 30 meshes to the 

 inch (No. 50), or through a cheese-cloth backed by common 

 window screen. Stir constantly while adding the lime. Add 

 water to make the amount up to 50 gallons. 



