THE GRANVILLE TOBACCO WILT. 19 
NEW EXPERIMENTS. 
‘Experiments by the writer in the summer of 1908 have demonstrated 
that the Carolina tobacco disease is readily communicated to tomatoes 
through the root system. These infections were obtained by trans- 
planting healthy tomatoes into a bed of good hothouse soil in which 
tobacco plants affected by the Granville wilt had been buried recently. 
The stems of these tobacco plants, which were obtained from North 
Carolina, were swarming with the bacteria peculiar to this disease. 
The tomato plants were infected through broken roots, the plants 
being of considerable size when set into the infected bed. 
The experiment was begun at the end of July, and up to this date 
(August 18) nineteen tomato plants have contracted the disease. This 
disease is typical tomato wilt, the vascular bundles of stems and mid- 
ribs being browned and their vessels filled with the grayish white 
bacterial slime peculiar to the genuine tomato disease. Dissections 
showed the brown stain and the bacteria in the bundles to be more 
abundant as one passed from the top of the plant toward the roots, and 
always one or more broken roots were found diseased to the very end, 
i. e., browned and occupied by the bacteria. Most of the roots, how- 
ever, as well as all of the underground stem and all of the parts above 
ground, were free from external appearance of disease other than the 
wilt, i.e., from wounds, spots, or stains. The wilting was sudden,1.e., 
not preceded by any yellowing of the foliage. Numerous incipient 
roots developed on the stems. No other tomato plants in the houses 
or on the grounds (several hundred) showed any signs of this disease. 
The Jimson weed (Datura stramonium) planted in this bed also 
contracted this disease through the root system. 
Moreover, with bacterial slime taken from the interior of four of 
these wilting tomato plants (upper part of the stem) I have caused the 
Granville tobacco wilt inside of two weeks on four large healthy tobacco 
plants, the bacteria being introduced into leaves and stems by means 
of needle pricks, and also by pulling off leaves and rubbing the scars 
with the crushed tomato stems. The signs of this tobacco disease so 
obtained were in every way characteristic—wilt of follage, darkening 
of the veins of the leaves, longitudinal dark stripes on the stem origi- 
nating from internal staining, brown stain of the vascular bundles of 
the stem and leaves, and vessels gorged with the characteristic bacteria. 
Some of the uninoculated leaves also dried out irregularly, and the 
apical leaves on the inoculated side of the stem became dwarfed and 
distorted. The inoculations were made in another hothouse (where no 
other Solanaceae were grown), the checks remained healthy, and when 
the wilting plants were cut for examination the root system in three 
of the four plants was still free from disease, the inoculations having 
been made at the top of the plants. Moreover, in all cases (four places 
on each plant) the disease began in the pricked and rubbed areas. 
141—11 
