244 SUCCESSFUL FARMING 



Treatment. — Soak the seed potatoes for two hours in formaldehyde 

 (1 pound in 30 gallons of water) or in corrosive sublimate (4 ounces in 30 

 gallons of water) for one and one-half hours. When the land becomes 

 infected, avoid the use of stable manure and lime, and rotate crops for 

 three to five years. 



Little Potato, Rosette, Stem Rot, Scurf (Rhizoctonia or Corticium 

 vagum, B. and C, var. solani, Burt.).- — This disease assumes different forms, 

 varying with the climatic conditions, soils and varieties. In very severe 

 cases many of the young plants fail to get through the ground. Many 

 that do get through are dwarfed and show a peculiar crinkling of the 

 foliage. The part of the stems below ground shows peculiar brownish 

 or black cankers. 



Treatment. — Soak seed potatoes in corrosive sublimate as recom- 

 mended for scab. 



Bacterial Wilt {Bacillus solanacearum, Smith). — The plants wilt 

 prematurely, become yellow, then black and dry. This disease attacks 

 tomatoes, tobacco, peppers and eggplants. 



Treatment. — Rotate crops, avoiding those that are susceptible. 



Tipburn. — This disease is due entirely to hot, dry weather. It causes 

 the leaves to dry at the tips and margins, roll up and break off. 



Note. — 'There are a number of other diseases of the potato which 

 cannot be included in this brief discussion. 



PEANUT 

 Peanuts are subject to several foliage and root diseases of more or 

 less importance. Growers of this crop should consult with their state 

 agricultural experiment station. 



TOBACCO 



Granville Tobacco Wilt (B. solenacerarum, Smith). — This is due to the 

 same organism as the wilt of the potato, tomato, peppers and eggplants. 

 (See Potato.) 



Mosaic, Calico or Mottle Top. — The cause of this disease is still some- 

 what uncertain. The leaves of the diseased plants show dark and light 

 areas and frequently irregular thickenings or twistings. 



Treatment. — Remove the diseased plants. Be careful not to touch 

 healthy plants while working with the diseased plants. The disease can 

 be communicated by contact. 



Leaf Spots. — There are a number of leaf spot diseases and also mildews 

 which cause more or less trouble. 



Root Rots (Thielavia basicola, Zopf.). — This disease is a rotting of 

 the roots, accompanied by the production of numerous new roots. The 

 affected plants are dwarfed and frequently killed. 



Treatment. — Sterilize seed-bed. Rotate crops. Avoid liming and 

 acid fertilizers. 



