78 Halsted : Mvcological Notes 



The following table shows the amounts of sulphur per acre, 



and the time of application : 



Plot 



ti 



a 



a 



a 



I Tlclt 



2 



I20 lbs. 



1S96 4S0 lbs. 



II " 



2 



240 ** 



** 240 '* 



III '' 



2 



600 '' 



i < 



III « 



6 





4S0 ** 



IV " 



6 



300 '' 



1S95 



1S98 ^ 600 lbs. Scab 28.33 fc 



480 ** " 31.66 fc 



600 *' ^' 36.66 ^ 

 " 480 *' '' 20.00 fo 



300 " *' 10.00 % 



Average 25.33 % 



All of the ''seed'' for the whole field, except that of certain 

 check belts, was soaked twice for one hour each in the standard 

 solution of corrosive sublimate and this operation reduced the 

 scab 8^ %. After making this allow^ance for the corrosive sub- 

 limate the sulphur still further reduced the scab from 52 to 25.33 

 per cent., or to less than half of the average of the unsulphured 

 belts. 



In another part of the Experiment Area there were eighteen 

 belts of land in potatoes, and here the three untreated belts gave 

 63.30 per cent; of scab. There w^ere four belts to which sulphur 

 was added in equal amounts, but at different times, as follows : 



Belt I. 3 5 6 

 In 1S96. 240 Ills. 480 lbs. 360 lbs. 



In 1898 4S0 '* 240 '* 720 lbs. 360 

 Total 720 *' 720 ^* 720 *' 720 



a 



t< 



The average percentage of scab upon these four belts is 12.50^0 

 or 50.80^ below that upon the untreated belts. 



One other test was made w^ith sulphur for potato scab, namely 

 in a plot where turnips had been grown for four years continuously, 

 two crops each year, and sulphur at the rate of 1,200 pounds per 

 acre had been added to one belt in 1S96. 



After an hiterval of many years since potatoes had been upon 

 this land the scab was abundant, averaging 80^0 for the five belts 

 not bearing sulphur, while the treated one showed only 35^, and 

 three quarters of this was upon the row adjoining a belt wdiere the 



i 



scab w^as recorded as being gof). 



The three above experiments show that in one instance sulphur 

 reduced the amount of scab after the " seed" had been soaked 

 twice in corrosive sublimate from 52^ to 25.33^, in the second 

 case from 63.30^ to 12.50^ and in the last from 80^ to 35^. 

 An average of these results shows a reduction of the scab from 



65.io^> to 24.27^. 



