31 



Copper Sulphate. 



As was stated when dealing- with Bordeaux mixture, this compound 

 can be used to combat fungous diseases on plants, but if used in a solu- 

 tion concentrated enough to be of material benefit would destroy the 

 foliage. Nevertheless, for dormant wood it can be used quite freely, and 

 is recommended in the following strength : 



Water 15-25 gallons. 



Copper sulphate i pound. 



In dealing with grain smuts, however, where the strength of the solu- 

 tion is not so necessarily guarded, this substance has been found to be 

 decidedly beneficial. The Experiment Department of this College has 

 done some extended work in dealing with smutted grain, and report the 

 following results in connection with bluestone treatment with oats :* 



• (a) Copper sulphate i pound. 



Water 25 gallons. 



(b) Copper sulphate 1 pound. 



Water t gallon. 



In solution (a) smut affected grain was immersed for a period of 12 

 hours; and in (b) for a period of 5 minutes. After treatment the grain 

 was dried and sown in test plots, along with a check plot of some left 

 untreated. An average of three years' trial gave these data: 



Percentage of smutted heads. 



(a) treatment „ 0.2 



(b) treatment 1.1 



Untreated 7.0 



These results show that bluestone has a very decided action in check- 

 ing smut, and this is especially marked with treatment (a). 



Formalin. 



Formaldehyde is derived from marsh gas (Methane, CH^), the same 

 gas which everyone has seen emanating from all swamps and low places 

 where there is stagnant water, in the form of air bubbles. The formalde- 

 hyde is a gas, which under the influence of cold condenses to a clear 

 mobile liquid that boils at — 21° C. , and has the formula CH s O. If this 

 liquid be mixed with water until it forms 40 per cent, of the volume, 

 we have a commercial article known as "formalin," and which is used 

 and is valuable as a fungicide. It is especially useful as a treatment for 

 grain smuts and potato scab. 



Using the following strengths of formalin and method of treatment : 



(a) Formalin £ p i n t, 



Water 21 gallons, 



(Immersing for 20 minutes), 



(b) Formalin £ pint. 



Water 5 gallons, 



*Ont. Agri. College Bulletin 140, pp. 14-15. 



