208 MAINE AGRICULTURAL EXPERIMENT STATION. •IQII. 



in any way diseased or decayed. Others to disinfect and plant 

 the seed tubers just as they came from the bin, and others were 

 to try both methods. Those who were intending to plant only- 

 selected, treated seed were advised to reject all tubers when 

 cutting which showed any discolored areas in the flesh, par- 

 ticularly those which showe'd browned or blackened rings at 

 the stem end, no matter how slight. As a farther precaution 

 it was recommended that extra knives and a jar of formalde- 

 hyde solution be provided when cutting seed and if, by chance, 

 a diseased tuber was cut the knife blade could be dropped into 

 the disinfecting solution for a time and another used in its 

 place. Some were to disinfect by means of formaldehyde 

 solution and some were to use formaldehyde gas. It was also 

 suggested that selection of sound tubers without disinfection 

 be compared with the forms of treatment mentioned. 



The experimenters were cautioned not to allow treated seed 

 tubers to come in contact with tools, baskets, or barrels which 

 had been used for diseased or untreated seed. It was advised 

 that all containers for treated seed either be exposed to for- 

 maldehyde gas in a disinfecting chamber or washed out thor- 

 oughly with formaldehyde solution. Planters recently used 

 for contaminated seed were to have the parts which come in 

 contact with the seed pieces thoroughly washed and scrubbed in 

 formaldehyde solution. 



Those who used the liquid treatment immersed their seed 2 

 hours in a solution of one pint of 40 per cent, formaldehyde in 

 30 gallons of water. Where the formaldehyde gas treatment was 

 used the tubers were placed in open, slat-work crates and ex- 

 posed to the gas generated by means of potassium permanga- 

 nate, 'for from 12 to 24 hours in a tightly closed room con- 

 structed for the purpose. For each 1000 cubic feet of the 

 disinfecting chamber 3 pints of 40 per cent formaldehyde and 

 23 ounces of potassium permanganate were used. When, as in 

 some cases, a large proportion of the space in the disinfecting 

 chamber was occupied by crates of potato'es only about three- 

 fourths of the given amounts of the chemicals were used to 

 avoid too great concentration of the gas and possible resulting 

 injury to the germinating quality of the seed. 



