300 DISEASES OF ECONOMIC PLANTS 



not to complete eradication of the disease : The use of 

 light rather than heavy soils for the seed bed; avoidance 

 of excess of water or fertilizer ; the use of a new bed each 

 year; avoidance of too heavy seeding. 



Infested fields should be given a rotation to reUeve them 

 of tobacco temporarily. 



Granville wilt, bacUlose (Bacillus solanacearum E. F. 

 Smith'). — This wilt was first noted in print in 1903,^ 

 and it was first attributed to bacteria in September of the 

 same year.' It was known to tobacco growers in Granville 

 County, N.C., at least as early as 1881. It takes possession 

 of the soil, prohibiting successful tobacco culture in succeed- 

 ing years, and in sections where tobacco is the chief, possibly 

 the only, profitable money crop the advent of this disease 

 has caused great depreciation in farm values. 



The wilt is now known in North Carolina, Florida, 

 Georgia, possibly Connecticut, and what appears to be 

 the same disease has been described in Cuba, Porto Rico, 

 France, and Japan. 



The first indication of the disease is given thro.ugh the 

 leaves, which droop, becoming soft and flabby as though 

 suffering from want of water. This is not accompanied by 

 change in color ; the leaves remaining green for some time 

 after the wilt appears. A typical case is shown in Fig. 131. 

 Frequently the leaves on one side of the plant succumb 

 earlier than those on the other side, and even a single leaf 

 may show one-sided infection. The wilted leaves dry up, 



> Smith, E. F., U.S. Dept. Agr. Bur. Plant Indus. Bui. 141, part II, 

 1908. 



' Stevens, F. L., N.C. Agr. Exp. Sta. Press Bui. 11, August, 1903. 



» Stevens, F. L., and Sackett, W. C, N.C. Agr. Exp. Sta. Bui. 188, 1903. 



