FUNGOID DISKASKS OF I'OTATOFS 85 



presence of a minute fungus — Oospora scabies . Ijul 

 whether this same fundus is the cause of the scab 

 in Europe is still open to doubt, as owing to the 

 name scab being assigned indiscriminately to so 

 many skin diseases a considerable amount of con- 

 fusion exists. 



Lime and alkaline manures are credited with pro- 

 ducing scab, but while these substances may result 

 in a form of scab or in an apparent increase of the 

 attack, the true cause must be looked for in some 

 parasitic fungus, either similar to, or identical with, 

 that described by Thaxter. 



Whatever the true nature of the disease may be, 

 the preventive measures recommended by the 

 American investigators, and enumerated below, 

 might with advantage be adopted in this country. 



Preventive Measures. — 



1. Steep tubers to be used for planting in mercuric 

 chloride solution (p. 31). 



2. Plant tubers free from scab. 



3. Give infested land a rest from the crop. 



4. Do not plant the disinfected tubers in land 

 where potatoes or beets have developed scab in 

 previous years. 



VI. Wart Disease or Black Scai; {Cliryso- 



phlyctis endobiotica) — {SyjichytriuDi endobioticinji. 



Percival). Class : Phycomvcete.e ; Order : Chvtri- 



DIALES. 



This disease is common in Continental Europe, 



