36 Transactions of the Canadian Institute. [vol. x 



tion increases, as cultural methods become more intensive, and "im- 

 proved" varieties of crops are employed, the "improvement" of which 

 consists chiefly in the power of returning under favourable conditions a 

 larger yield, without reference to their power of disease resistance, seri- 

 ous diseases become more frequent in their occurrence and more de- 

 structive in their effects, unless special measures are taken to safe- 

 guard crops against them. Hence there is much work for the plant 

 pathologist who, by microscopic examination and cultural methods in 

 the laboratory and experiments in the greenhouse or field, isolates the 

 organisms which produce the diseases, studies their life history, determines 

 experimentally the conditions under which they become destructive and 

 the measures which may be successfully undertaken for their control. 

 Fungus diseases do much harm to orchard and field crops, reducing 

 yields and lowering the value of such produce as may be obtained. 

 Not infrequently the loss from a single disease of one particular crop 

 may in a season favourable to the disease amount to thousands of dollars, 

 as, for instance, in the case of Fire Blight of apple and pear trees, or 

 smut of wheat, or Late Blight of potatoes. These diseases cannot be 

 ignored. It is doubtful if there is a single crop immune from their attack 

 and, generally speaking, the more important the crop the greater the 

 number of diseases to which it is subject. It is, therefore, the duty of 

 the Botanist to carry on inquiries and investigations respecting the 

 control of the diseases which appear to most seriously interfere with the 

 work of the agriculturist and horticulturist in this country; to keep 

 himself informed of what is being done along similar lines at other centres 

 of investigation ; and to utilise the results of his own work and those of 

 his co-workers to furnish to the perplexed cultivator the best informa- 

 tion available on the subject. Among the diseases more particularly 

 under investigation at present are the Silver Leaf of fruit trees, Black 

 Rot of cherry and plum, Scab, " Rhizoctonia " and other diseases of 

 potatoes and Smut diseases of grain. 



The difficult problem of working out methods for the control and 

 eradication of noxious weeds and poisonous plants is another and im- 

 portant feature of the Botanist's work. 



The Botanist also has charge of the Arboretum at the Central 

 Farm in which there is to be found an extensive collection of hardy 

 trees, shrubs and perennials, the result of many years' experimentation 

 with plants from many distant parts of the world. In addition, an 

 effort is being made to gradually bring together a collection of native 

 plants which shall comprise all representatives of the Canadian Flora 

 hardy enough to be grown at the Farm without special protection, to- 



