468 Report of the Mycologist op the 



whether the treatment was beneficial or otherwise. (This ap- 

 plies not only to tests of Bordeaux mixture but to tests of all 

 other fungicides as well.) Without such a check for comparison 

 an experiment has but little value. If the disease disappears 

 under treatment such disappearance may be due to the treatment 

 or it may be due to something else. Carnation rust is very ca- 

 pricious in its behavior. I know of at least one case and have 

 heard of several others where plants badly rusted completely 

 recovered without any treatment whatever. 



The exception above noted is an account of a spraying experi- 

 ment made by W. R. Beattie* at Columbus, Ohio. A bench of 

 badly rusted plants of the variety Tidal Wave was divided into 

 plots and sprayed weekly with solutions prepared according to 

 the following formulae: 



(1.) Bordeaux mixture: — 



Copper sulphate, six pounds; 

 Quick lime, five pounds; 

 Water, twenty-two gallons. 



(2.) Sulphide of potassium: — Two ounces to 22 gallons water. 



(3.) Chloride of copper: — Three ounces to 22 gallons water. 



"After three applications had been made a marked difference 

 could be noticed between the sprayed and the unsprayed plants 

 especially in favor of Bordeaux mixture." In all, five applica- 

 tions were made and the three sprays were found about equal in 

 efficiency, "all showing a marked increase as compared with the 

 unsprayed." The author concludes that it is impossible to exter- 

 minate the disease by any means whatever when it has once 

 become established and efforts must therefore be directed to the 

 prevention rather than the cure of it. 



Carnation rust has received very little attention at the Experi- 

 ment Stations. Lodeman-j- at the Cornell Experiment Station 

 claims to have cured badly rusted carnations by two applications 

 of Bordeaux mixture. As no untreated plants were left for a 

 check his results cannot be taken as proof of the efficacy of 

 Bordeaux mixture. 



* Beattie, W. R., Carnation Rust. Florists' Exchange, Vol. VI., p. 493. 

 t Lodeman, E. G., Cornell Exp. Sta., Bull. No. 9G,-,p. 333. 



