170 FUXGI AND FUNGICIDES 



circumstances, unless they have been thoroughly cooked, 

 even if the land on which the manure is to be used is 

 not to be cropped with potatoes at once. (-4) In gen- 

 eral, any fertilizer is to be preferred to barnyard manure 

 for potatoes, whether the stock has been fed with dis- 

 eased potatoes or not. (5) If it is suspected that a crop 

 is scabbed, it is of great importance to dig the potatoes 

 as soon as possible after tbey are mature, since the seal- 

 spots increase in size, and deepen, as long as they are 

 left in the ground, and what is at first a comparatively 

 slight surface injury may be sufficiently extended to ren- 

 der tubers worthless, which would otherwise have been 

 marketable. 



Experiments at the Korth Dakota Station, by Pro- 

 fessor Bolley, show that the disease may be prevented by 

 soaking the seed in a weak solution of corrosive subli- 

 mate. Concerning its use, he says: ''One wishing to 

 try the corrosive sublimate treatment, if to no greater 

 extent thai* to assure the raising of healthy, smooth 

 potatoes sufficient for seed the following year, will find 

 it best to proceed about as follows : Procure an ordinary 

 barrel, and fit into the base a common wooden faucet. 

 Purchase of a druggist two ounces of finely pulverized 

 corrosive sublimate {Mercuric licliloridc). Empty this 

 all into two gallons of hot water, and allow it to stand 

 over night, or until, apparently, all dissolved. Place in 

 the barrel thirteen gallons of water, then pour in the 

 two gallon solution. Allow this solution to stand in 

 the barrel four or five hours, during which time it is 

 several times thoroughly agitated, to insure equality of 

 solution before using. Select as fair seed potatoes as 

 possible, wash off all the old dirt, and immerse as many 

 as you can or wish to treat at one time in the solution 

 one hour and thirty minutes. At the end of this time 

 turn off the solution into another vessel. The same 

 solution may thus be used a number of times, if wished. 



