

The Potatoe Plague. 63 



burn the leaves, for a field may appear secure from the 

 botrydis, when it is not so ; several leaves are attacked ; 

 these leaves throw the propagule on to the tubercles, which,' 

 if preserved for the purposes of reproduction, will spread the 

 plague the following year. 



If the potatoes themselves are attacked, it is essential to 

 separate as speedily as may be, the potatoes that are tainted 

 from those that are not. Turn the sound ones over to account 

 as soon as possible, for they are not noxious so long as the 

 rind does not become yellow. The diseased ones should be 

 burnt. 



As it is probable that the tubercles preserved for seed will 

 be infected with the spawn of the mushroom, it would be ad- 

 visable for cultivators who can, to procure tubercles for 

 reproduction from places where the present scourge is 

 unknown. 



In case of using for reproduction the tubercles of crops 

 visited by the plague tliis year, it will be necessary to sub- 

 mit them,, previous to planting, to the agency of lime, as it is 

 practised with wheat and all plants that are liable to invasion 

 by parasitical bodies. The process ought to be by the im- 

 mersion of the tubercles in lime water. Fifty pounds of 

 lime, a quarter of a pound of sulphate of copper, and six 

 pounds of marine salt, for twenty -five quarts of water, consti- 

 tute a preparation, the utility of which, in the destruction of 

 parasite vegetation, has been experienced by a great number 

 of well-informed cultivators. 



In the plantations of the spring of 1846, it is essential to 

 plant potatoes in fields as far as possible 'removed from those 

 actually infected this year, to avoid the danger from the 

 retention in the soil of the spawn of the fungus. 



The use of lime and manure salt, with a slight mixture of 

 sulphate of copper, is, as I have already said, of acknowl- 

 edged efficacy in the destruction of parasite germs. Conse- 



