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SECTION VIII. 

 DISEASES OF THE CROP. 



The potato is liable to several forms of disease, 

 chiefly brought about by fungal agencies. It is also 

 subject to attacks of insects, some of which cause great 

 injury. One disease, however, stands out pre-eminently 

 as causing the greatest loss to the grower, and this is 

 commonly spoken of as the potato disease. This 

 disease first caused serious loss in England in 1845, and 

 for nearly half a century it ran its own course unimpeded ; 

 but fortunately a check, if not an entire preventive, 

 has been brought into use in the form of a spraying of 

 sulphate of copper and lime in solution applied to the 

 leaves. For this, growers are indebted to M. A. Girard, 

 a Frenchman, who was acquainted with the beneficial 

 effect of the solution in checking fungal attacks on the 

 vine, and who recognised the possibility of its proving 

 equally serviceable in checking the potato disease. 

 After carefully testing its effect, he made known its 

 value in this direction, and it has been proved on all 

 sides to hold the disease in check sufficiently to 

 warrant its general adoption. 



The Potato Disease. 



The potato disease is caused by a fungus (Phytoph- 

 thora infestans, until recently commonly called Peron- 



K 



