28 FUNGOID DISEASES 



a little dip a piece of blue litmus paper 



into it ; if the paper remains blue the 



mixture is safe to use, if not add more 



lime and repeat the test. 



After straining- and repeated stirring, apply in 



the form of a fine spray in the quantities stated 



under the respective diseases — usually from 40 to 



80 gallons per acre. For small areas a knapsack 



sprayer answers very well, but for larger areas a 



horse sprayer should be used. 



2 and 3. Soda-Bordeattx and Soda-Lime Bor- 

 deatix. — The above are modifications of the orio-inal 

 Bordeaux Mixture ; their preparation is somewhat 

 critical, and since they possess no effectual advant- 

 age over the original solution, details as to mixing 

 will not be oiven. 



4. Copper StUphate Solution. — Very dilute solu- 

 tions of copper sulphate are sometimes used instead 

 of the Bordeaux Mixture, but since they are more 

 liable to injure the host plant, and do not stick to 

 the surface so well, they are not to be recommended 

 for general adoption. Dilute solutions are, how- 

 ever, of great value for the treatment of seed grain 

 for smut and bunt. A common recipe for this 

 purpose is the following : i lb. copper sulphate and 

 I gallon of water for each sack of wheat ; the grain 

 being spread on the floor and the mixture applied 

 by means of a watering can, while the grain is 

 being turned. The above mixture is a 10 per cent 



