324 Maine; agricui^turai, e;xpe;riment station. 1909. 



Liquid Disinfection. 

 No. I. 

 Corrosive sublimate 2 ounces 



Water 15 gallons. 



Immerse seed tubers for i-| hours in this solution. 



, No. 2. 



Formaldehyde (40% solution) 8 fluid ounces (-J pint). 



Water 15 gallons. 



Immerse seed tubers 2 hours in this solution. 



Corrosive sublimate dissolves readily in water, but wooden 

 containers must be used on account of its corrosive action upon 

 metals. On account of its poisonous nature the corrosive subli- 

 mate solution must be kept out of reach of animals which might 

 drink it, and the treated tubers should not be used for food; 

 There is no danger from the use of formaldehyde, it is non- 

 poisonous to the higher forms of animal life as ordinarily 

 used. Since both of these solutions are effective No. 2 is recom- 

 mended in preference wherever formaldehyde can be purchased, 

 for the reasons given above. 



, While no experiments have been tried upon the blackleg 

 organisms to determine the germicidal effect of formaldehyde 

 gas generated by means of potassium permanganate its suc- 

 cessful use in destroying the bacteria associated with certain 

 contagious diseases of man is well known. The writer has also 

 found this method equally, if not more effective, in treating 

 seed tubers for potato scab than soaking in the solutions already 

 mentioned. Therefore, if a large amount of seed tubers is to 

 be treated at one time the following gas treatment is recom- 

 mended. 



Disinfection with Formaldehyde Gas. 

 Potassium permanganate 23 ounces 



Formaldehyde (40% solution) 3 pints 



The above is sufficient for each 1000 cubic feet of space. 

 The disinfection with formaldehyde gas should be done before 

 the sprouts begin to start on the seed tubers. Place the seed 

 tubers in bushel crates or shallow slat-work bins in a room 

 where all cracks have been tightly stopped and the door made 



