'the potato disease* 703 



by preventing the spores from being washed or otherwise carried 

 down to them. When this is practised the rows of potatoes 

 should be wider apart than usual, to allow of plenty of loose 

 earth to be hoed up to make the ridges. Bending the haulm 

 of a diseased crop into the furrow on one side is also advised, 

 with a view of allowing the spores to fall on that part of the 

 surface of the soil beneath which there are no tubers. 



(e) When the haulm has been much affected by the fungus, 

 remove it from the ground before digging up the tubers : this 

 is said to partially diminish subsequent rotting in the store-shed 

 or clamp. 



(/) Be careful in the use of highly-nitrogenous manures, for 

 crops grown with excess of these are more susceptible to virulent 

 attacks than when manured with potash salts and phosphates. 



(g) As the fungus is specially aided in its development and 

 distribution by moist surroundings, drainage and the addition 

 of substances which will diminish the moisture of damp soils, 

 or which will allow the rapid percolation of water through the 

 ground, are advisable. 



(A) When properly carried out spraying the leaves of the 

 crop with ' Bordeaux mixture ' is the most efficient means at 

 present known for diminishing the Phytophthora disease. 



The mixture consists of copper sulphate and lime. Various 

 amounts of these constituents are employed, but a common 

 useful formula is : — 



prepared as follows : — 



Powder the copper sulphate, and then dissolve it in a moderate 

 quantity of hot water in an earthenware or wooden vessel. When 

 quite dissolved add 60 or 70 gallons of cold water to the 

 solution. 



