B. P. I.— 399. 
THE GRANVILLE TOBACCO WILT. 
By Erwin F. Situ, Pathologist in Charge of the Laboratory of Plant 
Pathology. 
HISTORY. 
Attention was first called to the Granville tobacco wilt in Septem- 
ber, 1903, by McKenney, then connected with this Department. He 
attributed it to a fungus (Fusarium) nearly related to those studied 
by the writer on cotton, melon, and cowpea. No proofs from inocu- 
lation were obtained by McKenney. 
A few days after the appearance of McKenney’s paper a bulletin 
was published by Stevens and Sackett, of the North Carolina Agri- 
cultural Experiment Station, describing this disease and attributing 
it to bacteria. Their diagnosis also depended solely on field observa- 
tions and microscopic studies, but this part of the work was well done. 
In 1905, as the result of personal examinations of infected plants, 
studies of the microorganism in pure cultures, and successful inocu- 
lations therefrom, the writer confirmed the findings of Stevens and 
Sackett as to the bacterial nature of this disease. Numerous success- 
ful infections of tobacco were obtained both by needle puncture from 
pure culture and by plantings in infected soil. 
The organism was identified provisionally as closely related to Bac- 
terium solanacearum, a species described by the writer in 1896 as the 
cause of a widespread and destructive brown rot of the potato, tomato, 
and eggplant. This conclusion was based on the similar behavior of 
the tobacco bacterium and of undoubted Bacterium solanacearum 
(derived from tomato and potato) in a variety of culture media. The 
shade of doubt remaining in my mind at that time was due to the fact 
that many cross-inoculations (potato to tobacco and tobacco to to- 
mato), while showing multiplication of bacteria in the inoculated 
tissues and some other signs of disease (brown stain in the bundles, 
and on tomato stems the development of incipient aerial roots), did 
not contract the wilt. 
THE CONTINUED PREVALENCE OF THE DISEASE. 
Both in North Carolina and in Florida this wilt of tobaceo has con- 
tinued with increasing severity, the losses in 1908 being greater than 
those of any previous year. In North Carolina quite a number of 
7034—Bul. 141—09 3 17 
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