2 CIRCULAR 682, U. S. DEPARTMENT OF AGRICULTURE 
provide a means both for conserving the farm labor that is wasted 
when disease destroys crops and for avoiding serious losses in the pro- 
duction of an important item in military provisions. 
As a first step in seeking material resistant to black shank, 66 flue- 
cured varieties, strains, and selections were tested, but none proved 
resistant. Two varieties of ordinary tobacco and three varieties of 
rustica tobacco obtained from Russia, however, were highly resistant, 
and two dark fire-cured hybrids proved moderately so. Four strains 
of cigar-wrapper tobacco developed and supplied by the North 
Florida Experiment Station were found highly resistant under Old 
Belt conditions in North Carolina, and one of these, known as 301, was ~ 
crossed with standard flue-cured varieties. By following the pro- 
cedure of selfing, selecting, and back-crossing to the flue-cured parents, 
the four fairly uniform strains resistant to black shank have now been 
obtained. These conform well with the flue-cured type and possess 
good quality. 
Although the new strains need to be somewhat further improved 
with respect to uniformity and quality of leaf, they are considered to be 
suitable for meeting the immediate urgent need for resistant types in 
the flue-cured producing areas where black shank is prevalent. 
A SERIOUS PROBLEM 
The fact that entire plantings may be destroyed by black shank 
creates a serious problem for tobacco growers, especially those who 
have limited areas suitable for production. The problem is compli- 
cated by the ease and rapidity with which the disease spreads. Out- 
breaks in North Carolina during the last few years indicate that within 
a very short time it may spread over the entire Old Belt (western 
Piedmont). As a result of localized outbreaks, flue-cured tobacco is 
being menaced in the Middle Belt (eastern Piedmont) and the New 
Belt (Coastal Plain). 
The disease has been reported in Brazil, Guatemala, Jamaica, 
Nyasaland, the Philippine Islands, Puerto Rico, Java, Mauritius, 
Rumania, Bulgaria, Argentina, Uganda, Trinidad, Japan, and For- 
mosa. In the United States, it is known to occur in Florida, Georgia, 
Alabama, North Carolina, Virginia, Kentucky, and Tennessee. Its 
first appearance in the flue-cured tobacco area of North Carolina 
was about 1915 in the vicinity of Belew Creek, Forsyth County, but 
it was not identified and did not cause general alarm until 1930. By 
1932 several isolated centers of infection had become established in 
other parts of Forsyth County, as well as in the adjoining counties of 
Guilford, Rockingham, Surry, Stokes, and Alamance. In 1941 the 
disease was general in the counties named and in addition had spread 
to Person, Davidson, and Pitt Counties, or about 200 miles from the 
nearest previously known disease center. During 1937 it was carried © 
into Mecklenburg County, Va., on diseased plants obtained from the 
black-shank-infected area in Pitt County, N. C., and later it was 
found in Pittsylvania and Halifax Counties, Va. 
