CHAPTER XXIV 

 FUNGI (continued) 



POTATO DISEASE (Reports, I, 150 ; XIV, i) 



THE ordinary potato disease (Phytophthora infestans) has prob- 

 ably been the subject of more trials and of more pamphlets than 

 any other disease. The importance of the potato crop, and the 

 disastrous degree to which it may be affected by the disease, is, 

 however, a sufficient explanation of this, as well as of the number 

 of the remedies advocated. 



All these remedies consist of copper in some form or another, 

 and an impartial consideration of the mass of literature on the 

 subject leads to a conclusion very much akin to that drawn in 

 the case of insecticides for caterpillars, namely, that no one of 

 them is superior to the others under all circumstances, but that 

 sometimes the one, or sometimes the other, may prove the best. 

 One of them may be the more suitable in a persistently wet 

 climate, or in an exceptionally wet season, the other may be the 

 best under drier conditions ; one may present facilities in its pre- 

 paration which others do not ; one may necessitate the use of 

 a larger amount of material than others in order to obtain the 

 same results ; or, again, one may entail the presence of by- 

 products which under certain circumstances may cause damage. 

 But with a suitable adjustment of the amount of material used, 

 or of the number of applications made, all these substances will 

 yield equally satisfactory results under certain stated conditions. 



It is much to be regretted, the re fore, -that a recently formed 

 Government Department that of Food Production should 

 have embarked on such a vigorous campaign in which they 

 are spending much public money in advocating one particular 

 remedy to the exclusion of all others, and that, too, without 

 having made any trials of the remedies in question, or without 

 even having made themselves acquainted with the nature of or the 

 proper way of making, either that which they advocate, or those 

 which they decry (see p. 183). It is true that at the present time 

 of writing (1918) the Department are having some belated trials 

 made ; but trials made with the object of justifying a course 

 R 241 



