DISEASES OP PLANTS. 799 



decreases scab when used with barnyard mauure, especially when used 

 in conjunction with salt. 



Tht' iiitiuence exerted by various calcium compounds on scab devel- 

 opment was investifiated and the results obtained are tabulated. From 

 these it appears that the chlorid and sulphate nearly or (juite pre- 

 veuted scab, although the first greatly reduced the yield. The carbon- 

 ate, oxalate, and acetate of sodium, air slacked lime, and wood ashes 

 tended to increase greatly the amount of badly scabbed tubers. The 

 unlimed pots gave a iiroduct without scab. 



In this series of experiments the seed tuViers were soaked for li 

 hours in a 1 : lOOO per cent solution of corrosive sublimate prior to plant- 

 ing. In the pots which were badly infested with the fungus causing 

 the scab and in which the conditions were fiivorable for its growth the 

 treatment was considered useless. 



The authors review some of the investigations of Halsted ' relative 

 to the efficiency of sulphur in combating potato scab. They conducted 

 some exi)eriments to test the value of this fungicide for use against 

 the scab fungus. In these experiments sulphur at the rate of 600 lbs. 

 per acre was thoroughly worked into the first 7 or 8 in. of the soil in 

 the pots; where the soil was contaminated and the conditions favor- 

 able for the growth of the fungus the crop was practically destroyed 

 by scab and in 2 instances no advantage seemed to have followed from 

 its use. The authors think that if suli)hur was not efficient when used 

 to the extent of 600 lbs. per acre, smaller quantities broadcasted or iu 

 the drills would prove of little or no value. The expense of sulphur 

 when applied iu such large quantities would prove a serious obstacle 

 to its use while the market value of potatoes remains as low as at 

 present. 



Experiments for the prevention of potato scab, T. A. Williams 

 {South Dakoiu Sta. BhJ.48,2>P- l-H)- — A report is given of experiments 

 with corrosive sublimate, Bordeaux mixture, and eitu celeste for the 

 prevention of potato scab. The results are tabulated, from which it is 

 seen that — 



"(1) Seed treated with corrosive sublimate will give a product practically free 

 from scab if planted in uuiufested land. 



"(2) Thorough treatment will very materially reduce the amount of scab when tiie 

 seed is planted in infested land. 



"(3) There seems to be very little difference in the effectiveness of the difii-rent 

 flolntions of corrosive sublimate used, so long as the time of immersion is kept pro- 

 portionate to the strength of the solution. More care is necessary, however, in using 

 the stronger solutions. 



"(4) In immersing it is best to treat the seed before cutting. 



"(5) Eau celeste and Bordeaux mixture are both effective against the scab fungus, 

 but both seem to affect the yield more or less. 



"(6) In tlio infested land spraying was (piite as effective as immersing when Bor- 

 deaux mixture or the stronger solutions of corrosive sublimate are used. It must bo 

 remembered, however, that the seed used was quite free from scab. 



»New Jersey Stas. Bui. 112 (E. S. R., 7, p. 780). 



