74 HORTICULTURIST'S RULE-BOOK. 



warmed room, at a temperature of about 70. Store only 

 sound and perfect tubers, and remove at once any which 

 are attacked. 



SOIL-KOT (Acrocystis Batatas, Ell. & Hals.). The tubers are 

 attacked when young, and the diseased portion ceases to 

 grow, causing the potato to become constricted or variously 

 contorted. 



Preventive. Rotation. It is probable that the sweet- 

 potato cannot be grown again safely on infested soil for a 

 number of years, without treatment. 



Remedy. When the furrows are open and ready for 

 planting, before the manure is added, spray the soil with 

 Bordeaux mixture. 



STEM-ROT, BLACK-SHANK. An obscure disease attacking the 

 young shoots near the ground and the tops of the young 

 tubers, causing the tubers to rot away above, and to send 

 up sprouts below the injured portion. 



Preventives. Rotation. Heat the soil used for seed-bed. 

 WHITE-MOLD or LEAF-MOLD (Cystopus Ipomcece-pandu- 

 rance, Farl.). The leaves become pale and brown patches 

 appear, and small whitish patches occur on the under sur- 

 face. It thrives upon the wild potato- vine or man-of-the- 

 earth (Ipomcea pandurata). 



Preventive. Destroy the wild potato-vine upon which 

 the fungus grows. 



Remedy. Some copper fungicide applied in a spray. 

 WHITE-ROT. This disease causes portions of the tuber to 

 become white and chalk-like, and sometimes the whole 

 tuber assumes a chalk-like consistency. 



Preventives. Use only healthy stock, and probably a rota- 

 tion of crops will be useful. 



Tomato. BLIGHT ( Cladosporiumfulvum, Cooke) . Soft brown 

 irregular spots appear on the under surface of the leaves, 

 and the upper surface becomes spotted with yellow. The 

 leaves finally shrivel. Most serious in greenhouses. 



Preventive. In houses, keep the temperature as even as 

 possible. In particular, avoid sudden changes. In mild 



