Circular no. 727 



July 1945 • Washington, D. C. 



UNITED STATES DEPARTMENT OF A( 



U&H 



Flue-Cured Tobacco Resistant to 

 Bacterial (Granville) Wilt 



By Thomas E. Smith, associate pathologist, Division of Tobacco Investigations, 

 Bureau of Plant Industry, Soils, and Agricultural Engineering, Agricultural 

 Research Administration, and the North Carolina Agricultural Experiment Sta- 

 tion; E. E. Clayton, senior pathologist, Division of Tobacco Investigations, 

 Bureau of Plant Industry, Soils, and Agricultural Engineering; and E. G. Moss, 

 senior agronomist, Division of Tobacco Investigations, and assistant director of the 

 Tobacco Branch Station, North Carolina Agricultural Experiment Station and 

 North Carolina Department of Agriculture 1 



CONTENTS 



Description of the disease- 

 Source of resistance 



Breeding work 



Description of Oxford 26.. 



Page 

 3 

 3 



4 

 4 



Fage 



Tests of yield and quality. 



Suggestions for culture 



Seed sources 



^wywwyw^ 



BACTERIAL (Granville) wilt is one of the most common and 

 destructive diseases of tobacco. First reported in 1903 in localized 

 areas of southern Granville County, N. C, the disease has since be- 

 come widespread in the flue-cured belt of North Carolina and Virginia 

 and is also present in South Carolina and Georgia. Within recent 

 years the disease has caused increased losses in the most intensive 

 tobacco-producing areas of eastern North Carolina, but the greatest 

 loss has occurred in the north central part of the State. 



About 20 percent of the crop has been destroyed each year in 

 Granville, Wake, and Durham Counties, and losses on some farms 

 have been as high as 90 percent. From repeated surveys it has been 

 estimated that during the past 10 years bacterial wilt has reduced the 

 tobacco crop by 10 million pounds annually. This means an average 

 loss each year of 2 million dollars on the basis of the price for the 6-year 

 period 1935-40. Tobacco production has been so badly disrupted in 

 southern Granville County and in adjoining areas that the value of 

 wilt-infected farms has been greatly depreciated. 



Much research on wilt has been conducted during the past 40 years 

 both in this and in other countries. Crop rotation and sanitary prac- 

 tices have reduced the losses, with the result that growers having 

 infected fields have been able to continue tobacco production. That 

 these practices have not been adequate, however, is shown by the 

 continuing spread of the disease and resulting increased losses. Soil 

 treatment with urea in combination with a rotation of corn has been 

 found to provide satisfactory control, but the cost of the chemical is 



i Acknowledgment is made to F. R. Darkis, of the Chemistry Department of Duke University, for 

 evaluation of quality; and to H. R. Garriss, North Carolina Extension Service, E. K. Vaughan, formerly of 

 the Virginia Agricultural Extension Service, and W. A. Jenkins, of the Virginia Agricultural Experiment 

 Station, for supervision of trial plantings at many locations in these two States. 



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