2 DISEASES OF CULTIVATED PLANTS 



present day than heretofore is an open question, and can 

 only be answered by a comparison of the area under cultiva- 

 tion with the annual loss due to disease at the present day, 

 as compared with that of some twenty-five years ago, which 

 is an impossibility. 



There are many causes which favour the spread and 

 increase of disease at the present day, which had no existence 

 in bygone times; perhaps the most potent is that commonly 

 known as 'rapid transit.' 



Undoubtedly a change of seed is good, but, as experience 

 has proved, you never know what disease you are intro- 

 ducing, and in many instances it is impossible to detect 

 anything wrong until too late. The facility with which 

 seeds, tubers, and even living plants can now be sent to the 

 uttermost parts of the earth is a source of great danger from 

 the point of view of introducing new diseases, and unless 

 something in the way of a quarantine is insisted upon in 

 every country, it appears highly probable that in course of 

 time those diseases, which assume the proportions of an 

 epidemic, will be equally abundant wherever the host-plant 

 is cultivated. Where total prohibition is not considered 

 necessary, quarantine, which has answered so well in the 

 case of animal diseases, might with advantage be applied in 

 the case of fruit-trees, etc The trees should be planted in 

 some suitable place, and be examined from time to time by 

 some quali f u < 1 person. After a season's growth they might 

 be allowed to pass into the country, if free from disease. 



I am quite aware that some people will say this idea 

 is not practicable, and further, such precautions are not 

 necessary. There is certainly nothing impracticable; it is 

 quite as easy to plant a tree in one place as another. The 

 cost of a tree that has been in quarantine for a season would 

 i ertainly cost more than it would at the moment of landing, 

 but on the one hand the purchaser would secure a tree free 

 from disease, whereas on the other hand the tree might 

 prove to be infected with some disease. The fact that the 

 most destructive diseases attacking fruit-trees and other 

 plants in Europe, also eventually appear in whatever part of 

 the world such trees are cultivated, is absolute proof that 

 the disease lias been conveyed along with the plant. 



