1913. 



PUBLIC DOCITMENT — No. 31, 



93 



The yield was small, however, both on the treated tiles and the 

 checks. 



The series treated with carbon bisulfid showed some results, 

 the cheek tiles averaging 50 per cent, scab and the treated tiles 

 showing an average of 20 per cent. 



It can be seen that this year's resnlts are showing some im- 

 provement over those of preceding years, and by elimination 

 only the most nsefnl compounds are to be used hereafter, with 

 perhaps one or two additions. 



Table IV. — ■ Plan of Potato Scab Experiments, 1912. ^ 



Pot 

 Num- 

 ber. 



Substance used. 



Amount used. 



By-product A, 

 By-product A, 

 By-product A, 

 By-product A, 

 By-product A, 

 By-product A, 

 Sulfur, . 

 Sulfur, 

 Sulfur, . 

 Naphthalene, . 

 Steam-sterilized, 

 Steam-sterilized, 

 Steam-sterilized, 

 Formalin, 1-100, 

 Formalin, 1-200, 

 Formalin, 1-300, 

 Formalin, 1-400, 

 Carbon bisulfid. 

 Carbon bisulfid, 

 Carbon bisulfid, 

 Nicine, 

 Nicine, 



100 grams (dry). 

 300 grams (dry). 

 500 grams (dry) . 

 100 grams (wet). 

 200 grams (wet). 

 300 grams (wet). 

 50 grams (wet). 

 100 grams. 

 200 grama. 

 50 grams. 



15 cubic centimeters. 

 25 cubic centimeters. 

 40 cubic centimeters. 

 100 grams. 

 200 grams. 



1 Numbers omitted were used as check tile. Potatoes treated exactly as in preceding experi- 

 ments. 



In 1012 the experiments were carried on in a similar man- 

 ner, bnt for the most part chemical solids were used, with the 



