150 EXPERIMENT STATION. [Jan. 



for spraying would in such instances be more wisely used in 

 methods of cultivation. Some of our best landscape gardeners 

 have advocated that, if $25 were to be used in planting a 

 tree, about $23.50 of it should be used for preparation ; and 

 such advice is based upon the best agricultural practices. If 

 intensive agricultural methods were applied more often to the 

 growing of plants, pathologists would have much less diagnos- 

 ing of diseases to do. 



Every influence which may in any way affect plants should 

 be carefully studied. We should understand what influence 

 the chemical, physical and biological properties of soil, ma- 

 nures, fertilizers, air drainage, etc., have upon susceptibility 

 to disease. The plant organism is an extremely complex 

 mechanism, very plastic and responsive, and is continually 

 being acted upon by a number of forces or stimuli which in 

 turn produce a series of self-regulatory and correlative re- 

 actions. Undoubtedly in the future the control of plant dis- 

 eases will depend more upon breeding and cultural conditions 

 than now ; but for the present, spraying must be employed 

 when practicable for the control of diseases until something 

 better shall have been discovered. 



