212 The Ottawa Naturalist [Mar. 



fertilit}^ could not be considered without reference to their 

 biological aspects which are really the fundaments. 



The Prevention of Losses Incident to the Products 



OF the Soil. 



Having taken all the means that are necessary to conserve 

 the fertility of the soil, we are faced, in the production of our 

 crops, whether they may be farm or fruit crops, with serious 

 factors which, if not contended, will more than counterbalance 

 the advantage gained in such conservation. Therefore the com- 

 batting of those factors adverse to successful cultivation and 

 production is an integral and essential part of conservation. 

 Of such adverse factors, the chief are plant diseases and insect 

 pests, and I shall consider the latter more particularly as we have 

 at present more accurate data and statistics with regard to their 

 depredations. The immense losses which insects and plant 

 diseases incur are chiefly due to the disturbance of natural con- 

 ditions brought about when man cultivates the soil and provides 

 large quantities of eminently suitable food for insects often 

 previously subsisting on wild plants. It is generally conceded 

 that a ten per cent, basis may be taken as the average loss on 

 farm crops due to injurious insects, and those who have 

 given their continued attention to the question consider 

 that this is the minimum. On that basis Marlatt estimates 

 that the annual loss in plant products of the farm in the 

 United States, due to insects, is $650,000,000, and on the 

 same basis our annual loss in Canada would be over $50,000,000 

 worth of farm crops. In fruit production insects make a tax 

 of at least thirty per cent, and Chittenden puts the total 

 losses, plus the cost of treatment, at over $66,000,000 in the 

 United States. To the ordinary person these figures seem 

 incomprehensible, but this loss is capable of estimation on the 

 basis of experience, and those of us who are dealing with these 

 losses daily have no hesitation in maintaining that ten per cent. 

 is a minimum average .loss. This is omitting the losses, 

 which are no less serious, due to plant diseases, and those which 

 are due to weeds. It is safe to say that, even w'ith our present 

 knowledge of the methods of combatting these pests, we can 

 effect a saving of at least thirtv per cent., and with the increase 

 of such knowledge, which can only be gained by scientific in- 

 vestigation, that percentage will gradually increase. It is nec- 

 essary that it shall increase, for the soil of Canada supplies the 

 food not only of our own people but of other nations who are 

 looking to the new world and the west for their food supplies. 



The conservation of the soil, therefore, rests on two principles 



