968 EXPERIMENT STATION RECORD. 



were moistened and rolled iu sulphur at the rate of 300 lbs. per acre, 

 the sulphur uot adhering to the tubers being dusted over them before 

 covering by the soil; and other tubers received no treatment. The 

 results obtained showed that the sulphur treatment was slightly more 

 efficient than corrosive sublimate, and also that the disease germs were 

 present in great quantities iu the soil, as otherwise the corrosive subli- 

 mate treatment would have reduced the amount of scab as compared 

 with no treatment. 



In the second series of experiments the same pots and soil were used 

 as in previous experiments, which had been treated with lime, wood 

 ashes, calcium chlorid, sulphate, carbonate, oxalate, or acetate. The 

 seed tubers were washed before attempting to examine them for scab. 

 All the tubers were treated with 1 : 1,000 corrosive sublimate solution 

 for li hours before planting. Iu addition, a part of the tubers were 

 treated with sulphur iu the same manner as in the first experiments. 

 The efficiency of the acid soil and calcium sulphate and chlorid in pre- 

 venting the development of scab was shown, not a trace of scab being 

 found where either of the calcium compounds were applied. The poi- 

 sonous action of these substances on the crop was quite markedly indi- 

 cated, as in previous years' experiments. Comparing the sulphur and 

 corrosive sublimate treatment for the prevention of scab, it was found 

 that there was a reduction of about 21 per cent in the number of badly 

 scabbed tubers where sulphur was used. 



In consideration of the cost of sulphur when applied in large quan- 

 tities, and owing to the fact that it has little or no manurial action, the 

 results are compared with the favorable results previously obtained 

 with sulphate of ammonia, and further experiments in this line are 

 promised. 



The authors summarize their results as follows: 



"The results of 1897 fully confirm those of previous years as to the tendency of 

 carhonate of lime, and all combinations of lime which are changed into that lorm 

 within the soil, to promote in a striking degree the development of the potato scab. 



"On a badly contaminated soil the use of sulphur for 2 consecutive years, in quan- 

 tities amounting in all to 900 lbs. per acre, reduced the amount of scab in a decided 

 degree. 



"Owing to the cost of sulphur, and the improbability of its being of more than 

 slight, if any, indirect manurial value, it appears possible that the employment of 

 sulphate of ammonia, which is at the same time a valuable source of nitrogen, 

 might prove more economical than sulphur in reducing the tendency to scab on soils 

 already contaminated with the scab fungus. The results thus far secured indicate 

 that if it were employed in connection with kainit, sulphate, or muriate of potash, 

 soils would be rapidly improved in this particular. 



"Owing to the fact that soils naturally favorable to the development of the potato 

 scab are also favorable to nitrification, the fullest manurial action of the sulphate of 

 ammonia should be obtained." 



The asparagus rust, L. F. Kinney {Rhode Island Sta. Rpt. 1897, pp. 

 317-321). — During the summer of 1897 the asparagus rust (Puccinia 

 asparagi) made its appearance in various Rhode Island market gardens. 



