Vegetable and Field Crops 



265 



Sooty-mold (Fumago vagans Pers.). — Dense, olive-black 

 growths of mold form upon the leaves. Damping-ofif occurs 

 in the seed bed. Timber-rot {Sderotinia) , see lettuce. 

 Buckeye-rot {Phytophfhora terrestria) is a zonate, hard rot of 

 fruit. Winter-blight. — Loss of $2,500 in one house is re- 

 ported, but the disease is not generally distributed. Develop- 

 ment is dwarfed, and the stems show brown lesions in cortex 

 and bundles, but no parasite has been demonstrated. Ro- 

 sette ^^^ {Corticinm, vagum). — This is identical with the 

 potato black-scurf, showing 

 similar lesions upon the root 

 and stem near the ground. 

 The tops have long inter- 

 nodes and dwarfed leaves 

 which are somewhat curled. 



Upon the ripe fruits, espe- 

 cially those touching the 

 ground, this disease occurs 

 as a brown rot upon a 

 slightly wrinkled epidermis. 

 Hollow-stem appears to be 

 due to miproper growth con- 

 ditions. Blossom-drop is due to unknown cause. Leaf -roll is 

 similar to that of potato. Root-knot (nematodes) is common. 



(Edema.^^'' — This is a condition of overgrowth of certain 

 cells of the plant, causing swelling of veins and leaf tissues, 

 and curling of the leaves in irregular growth. Usually 

 confined to the greenhouse, it is caused by excess of water, 

 lack of light, improper temperature, and especially by over- 

 heated soil, and is readily controlled by careful management. 



Chlorosis. — The leaves show completely whitened areas. 

 The cause is unknown. Mosaic. — Upon the tomato appears 

 a mosaic, similar to that of tobacco. Aside from this ap- 

 parent kinship little is known about it. 



TURNIP. See p. 165. 



WATERMELON. See p. 178. 



i^^sat^ 



Fig. 144.- 



— Tomato anthracnose. 

 After Heald. 



