Notes on Apple and Potato Diseases in 1898 



BY H H. LAMSON 



Tlie principal fungous diseases of the potato are the scab^ 

 the early blight^ and the late blight. Each of these is due to 

 a minute parasitic plant which finds in the potato a congenial 

 host plant, and develops on it to its serious damage. The scab 

 attacks the tubers, the early bligJit the leaves, and the late 

 blight all parts of the plant producing in the tubers the disease 

 known ^.^ potato rot. Each of these diseases is propagated by 

 means of spores or germs which bear the same relation to the 

 fungous plant that seeds do to the higher plants. 



POTATO SCAB 



This disease affects the surfifce of the tubers, producing the 

 familiar scabby or scurfy appearance. The crop is infected 

 either by germs on the seed planted or by germs already pres- 

 ent in the soil derived from a previous crop. These facts lead 

 to the following practical suggestions as to treatment of the 

 disease : Plant seed known to be free from scab or seed which 

 has been freed from living germs by some method of disinfec- 

 tion ; do not plant on ground from which a scabby crop has 

 previously been taken. 



Since under ordinary circumstances it is difficult to obtain 

 seed entirely free from scab germs, some method of disinfection 

 becomes an important consideration. Three substances in par- 

 ticular have been recommended for this purpose, corrosive 

 sublimate, formaline, and sulphur. 



Corrosive Subli7nate. — In previous bulletins of this Station 

 experiments have been described in which this substance was 

 used with profitable results. The following additional experi- 



