' REPORT OF THE SOCIETY 105 



Size of Plots and Replications. 



Owing to the act that plans had already been laid for the season's work, 

 it was impossible to obtain the use of much land. Hence the plots could not be 

 replicated. They were one-hundredth acre each in extent. 



Consideration of Results. 



As was to be expected the germination of Hull-less oats was materially 

 reduced by the formaldehyde treatments. It appears, however, that the copper 

 carbonate and copper sulphate — lime treatments stimulated germination. This 

 statement is made advisedly since more tests should be carried out to detter- 

 mine actually if there is stimulation. 



In the control of smut both copper sulphate — lime dust and copper carbo- 

 nate dust were as effective as the formaldehyde spray within the limits of the 

 experiment. 



A STUDY OF SOFT ROT OF IRIS. 



By J. K. Richardson, B.S.A., M.Sc. 



Introduction. 



An important horticultural crop is the Iris of which some two hundred and 

 fifty varieties have been grown at Macdonald College. Of these, approxima- 

 tely one hundred and twenty varieties have died out as a result of disease during 

 the last five years. So far as the writer can ascertain, this loss has been mainly 

 due to "Soft rot" of the plants. Such a soft rot has been described in Europe 

 by Van Hall (10) and a rhizome rot is mentioned by Howitt (5) in Canada. 

 It is the aim of the writer to show by this investigation the cause of Iris soft rot 

 in Quebec, to study the pathological histology and, if possible, to compare the 

 causal organism with that described by Van Hall. 



Hosts. 



Bacterial soft rots are prevalent in all parts of the coun;try, and the disease 

 occurs on a wide variety of hosts. Erwin F. Smith (9) reports the disease of 

 cabbage, cauliflower, turnip, parsley, celery, lettuce, callalily, radish, cucumber, 

 musk-melon, potato, tomato, pepper, eggplant, hyacinth, onion, rutabaga, and 

 salsify. He also states that in all these cases, with the exception of the last two, 

 rutabaga and salsify. Bacillus Carotovorus has been isolated in pure culture. 



