2 Introduction. 



destruction have run as fast. To make up for so much lost time 

 we have been taking impossible jumps, and it seems our fruit-growers 

 who should benefit are those who suffer for the fall. The fruit- 

 grower must place reliance in anything that scientific knowledge can 

 give him, but he must not expect science to perform prodigies. At 

 present it is only a little that the entomologist or chemist can do that 

 can actually benefit the fruit-grower. They must go on building up 

 knowledge, and here and there, as in medicine, it will lead to some 

 definite success, some treatment that will cope with some particular 

 disease. 



After all the centuries of medical investigation, of medical treat- 

 ment, of medical records, would any sane man be duped by a 

 " quack " selling a pill or a bottle of mixture that is so complete it 

 would cure all man's ills ? Yet we seem to call to mind many who 

 imagined a few years' work on totally unknown subjects had accom- 

 plished such an extraordinary thing in connection with plant diseases. 

 The diseases of fruit trees, like those of man, must be treated 

 according to their various ways, with the same wide variants ; and 

 for them we may say there are many palliatives, but few actual 

 remedies. We have yet so much to learn, first of the diseases, then 

 of how to treat them. 



Methods of how to prevent and how to treat the diseases of 

 fruit, caused by insect pests, are given in this volume. Many must 

 be taken as mere suggestions, successful in one place but perhaps 

 useless in another or under different circumstances. Can such treat- 

 ment be called a " cure " ? Time, material, environment, health of the 

 treated trees have all to be taken into account. A certain dose of 

 one particular drug for a certain man is good, it may be too much, or 

 too little, or actually harmful to another. Is not this likely to be the 

 same in the treatment of our fruit trees ? 



How can we best help the fruit-grower by " science," since he 

 cannot, at this present decade, have a " consultant " always at hand. 

 The only way is to enable him to tell what disease his trees or 

 bushes are suffering from, and so to learn all he can about such a 

 disease. Given this knowledge he can himself apply what known 

 remedies we have, how and when the local circumstances seem best. 

 It is with the object of placing before growers a condensed account 

 of the numerous insects, mites, etc., that live upon and, we may say, 

 cause disease to his trees and bushes that this book has been written. 



It could never have been done had it not been for those very men 

 whom the writer hopes, to give some little help to, for the idea of 

 how to see and how to follow these strange, yet beautiful insects, in 



