SPRAYING 



From what has already been said, it must be evident 

 that spraying will always have to be adapted, both as 

 regards the date of the operation and the substances 

 used, to the nature of the pest to be dealt with. The 

 idea of having some one substance which will cure all 

 the ills to which a tree is liable, is just as unlikely of 

 realisation, as is that of some panacea for all the 

 diseases to which human beings are prone. Never- 

 theless, a simplification of the treatment of trees is 

 highly desirable, and this has been attempted in the 

 present treatise. Instead of giving all the remedies 

 which have ever been recommended for each individual 

 pest, the most promising one or ones (in the opinion 

 of the authors) have alone been mentioned ; and, where 

 a number of equally efficacious remedies appear to 

 exist, preference has been given to that which is 

 applicable in other cases as well. 



It must be borne in mind that by far the greater 

 number of pests have not yet been made the subject 

 of careful study from the point of view of the best 

 means of destroying them, and, till that has been 

 done, all recommendations must contain a consider- 

 able element of uncertainty. Growers who are 

 sufficiently interested in the matter to wish to make 

 themselves acquainted with the evidence on which 



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