EXPERIMENT STATION BULLETINS 



321 



Chlorine gas, to which 'the seed was exposed for three hours in a tight receptacle. 

 (8) CoiTosive sublimate, at the rate of one part to two thousand of water, in which 

 the seed was soalied for one-half hour. 



Rows forty feet long were planted with seed that had been treated in each of the 

 above ways, and four additional rows were planted with seed that had not been 

 treated as a check. A record was kept of the number that grew with each of the treat- 

 ments, and when the crop was harvested, the per cent of tubers that were scabbed 

 was determined. The results are given in the following table, with the cost of each 

 treatment for one acre of potatoes: 



Scab Experiment. 



Material Used. 



Chloride of lime lu the hills. 

 Chloride of liiiie 5% solutlou. 

 Formaldehyde ^as 



Formalin solution V4^ 



Lj'sol solution Xi ■ 



Carbolic acid solution 2% 



Chlorine gas 



Corrosive sublimate (1-2000). 

 Nothing 



Manner of Application. 



Sprinkled on the seed dry. 



Soaked seed 3 hours 



In closed receptacle 2 hrs. 



Soaktd seed 3 hours. 



'■ " 4 •> . 



'• 6 " . 



" 10 " . 



bi «t Cit bb 



Soaked seed 2 hours. 



4 " . 



" " 6 " . 



" 10 " . 



Soaked so(d 2 hours. 

 " " 4 " . 



" " 6 " 



" " 10 " . 



In tight receptacle 3 hours 

 Soaked seed >^ hour 



Per cent 



of Plants 



that Grew. 



10 

 75 











35 



yo 



8 

 4 



60 



48 

 35 



7 





 

 

 



20 

 100 

 100 



Per cent 



of 

 Potatoes 

 Scabbed. 





 10 

 1 

 

 



3 

 1 

 1 

 

 



10 



Cost of 



Material 



per acre, 



cents. 



50 



33 

 6 

 6 

 6 



10 

 111 

 10 

 10 

 10 



30 

 20 

 ~'0 

 20 



55 

 55 



55 

 55 



10 

 4 

 



It will be noticed that the five per cent solution of chloride of lime destroyed 

 25 per cent of the seed but produced no effect on the amount of scab 

 upon those that grew. When used dry in the hills, the injury was less 

 severe, but only 10 per cent of the plants grew. The result, so far as the pre- 

 vention of scab was concerued, seemed to be satisfactory, as all of the tubers were 

 smooth. Formaldehyde gas also had an injurious effect upon the development of 

 the seed, as after being treated with the gas in a closed receptacle for two hours, 

 three-fourths of the seed failed to grow, and the plants that did develop were quite 

 weak and spindling, and very few of the tubers were merchantable. The gas, how- 

 ever, seemed to be effective in preventing the scab, as only one per cent were scab 

 affected, while the untreated rows averaged 10 per cent. In the rows where the seed 

 had been treated five and seven hours with formaldehyde gas, no plants appeared. 

 One-half per cent formalin also seemed to have an injurious effect upon the develop- 

 ment, as when seed was soaked for two hours a slight injury was noticed, and after 

 twenty -four hours, only four per cent grew. A small amount of scab was found 

 where the treatment ranged from two to six hours, but with the longer treatments 

 no scab was apparent. The results with a one-half per cent solution of lysol 

 were similar to those secured with formalin, except that the injurious effect upon 

 the seed was more marked. When the two per cent solution of carbolic acid was 

 used, none of the plants grew, and with chlorine gas, only twenty per cent of the 

 plants grew, but the plants that did develop showed only slight traces of scab. 

 Corrosive sublimate at the rate of one to two thousand and with the seed soaked 

 one-half hour, seemed to have no injurious effect upon the growth of the plants, 

 and reduced the per cent of scabbed tubers to two, as compared with ten where the 

 seed was untreated. 



As will be noticed in the column giving the cost of materials per acre, the cor- 

 rosive sublimate treatment is cheapest of all, although the cost of the formalin 



41 



