TREATMENT FOR POTATO SCAB 13 



sulphate, and thirty-three with muriate of potash. The total 

 yield, however, was in favor of the muriate. The total weight 

 of those grown with sulphate was 1,978 pounds and 7 ounces, 

 and with muriate, 1,996 pounds and 9 ounces — making a differ- 

 ence of 18 pounds and 2 ounces in favor of the latter. 



In comparing the percentage of large and small potatoes, 

 there was but a slight difference. The weight of the large, or 

 marketable, potatoes with sulphate was 1,567 pounds, and with 

 muriate, 1,586 pounds, 19 pounds in favor of the latter. The 

 small potatoes yielded 411 pounds with sulphate, and 409 

 pounds with muriate. 



From the data obtained from this single year's test, little pref- 

 erence is shown for either of these forms of potash, as far as 

 yield is concerned. 



3. CORROSIVE SUBLIMATE TREATMENT FOR POTATO SCAB. 



Most of the trials in treating the potato seed before planting 

 with corrosive sublimate have proved it to be beneficial. 

 During the past season, we tested its efficiency upon each of the 

 eighty varieties grown. The soil, having been used for a potato 

 crop two years previously, was inoculated with the disease. One 

 half of each variety was placed in a coarse sack, and after soak- 

 ing one and one-half hours in a solution, in the proportion of 

 two ounces of corrosive sublimate to sixteen gallons of water, 

 was taken out and drained off; then cut and planted. Through- 

 out the fore part of the season the soil was comparatively dry, 

 but during the remainder was very moist, and offered exception- 

 ally favorable conditions for scab development, as it is well 

 known that moisture favors its growth. 



From the data secured, we arrive at the following results : 

 Two varieties, Nos. 60 and 68, were free from scab with both 

 treated and untreated seed. Two varieties, 3 and 58, showed 

 the same percentage of scab under both conditions. Sixty-two 

 varieties favored the treatment, while the remaining fourteen 

 did not. The total average for those treated was 24I per cent, 

 of scabby potatoes, while for those untreated it was 35^ per 

 cent. The efficiency of the treatment, therefore, was io| per 

 cent. Considering the fact that the soil was infected, and that 



