Apr. is, 1921 
Bacterial Spot of Tomato 
127 
The lesions frequently penetrate almost through the pericarp but ap¬ 
parently not into the juicy interior of the fruit. Coalescence of these 
lesions may cause very large blotchlike areas of disorganized pericarp 
tissue (PI. 24, C). As a general rule, no marked malformation of the 
fruit is produced. 
Associated with these lesions are often found small, circular, whitish 
“bird’s-eye” spots about 2 mm. in diameter with a dark raised central 
point or a lenticular rift at the center and a cavity under the white area 
(PI. 24, D). Cases were found in which the blackened scabs of the bac¬ 
terial spot had developed from the dark point at the center of the white 
spot and the white halo was less conspicuous. Preliminary attempts to 
isolate the bacterial spot organism from these white spots have been un¬ 
successful, and such lesions have never resulted from artificial inocula¬ 
tion. It has been assumed that these white “bird’s-eye” spots are a 
form of insect wound through which infection may occur. 
Needle-prick inoculation of fruit in the greenhouse has resulted in two 
types of lesions. Both steel needles and very fine capillary glass points 
have been used. In cases in which the needle was dipped in the inocu¬ 
lum and then inserted into the fruit, no superficial lesion resulted, but a 
rather firm blackish core of infected tissue was produced in the mesocarp 
well beneath the epidermis, resembling the apple bitter-pit type of lesion. 
When, however, the inoculum was applied to the surface of the fruit after 
the needle wounds were made, the lesions rather closely resembled those 
occurring in the field, except that the lesions were brown instead of black 
and caused more of a depression by their inhibition of fruit growth (PI. 
24, F). 
Bacterial spot lesions on the fruit may be differentiated from nailhead 
spot caused bv Macrosporium by their black or darker brown center, 
irregular margin, water-soaked border or halo, deeper penetration, and 
greater disintegration of the central tissues. Spots resulting from wound 
inoculation with Septoria lycopersici in the fruit also differed distinctly 
from the bacterial spot. 
O11 leaves of mature plants in the field, this disease causes small black 
spots with a slight tendency toward an angular outline (PI. 25, 1J). 
These spots may be greasy on the upper surface. The center may be at 
first translucent and the margin black. The central tissue soon becomes 
black and parchmentlike with a tendency to crack at the center. About 
the black center of such lesions, as examined in transmitted light, there 
is a distinct, yellowish, translucent margin. Lesions are more abundant 
on young leaves and often are confined to one or two leaflets of a leaf and 
to certain regions on each leaflet such as the basal portion or a lateral half. 
Among the seedlings in the fields noted in Georgia, this disease caused 
a conspicuous spotting of the leaves. There was in many cases a vellow 
discoloration of the tissue about the lesions, and badly spotted leaves 
were distinctly yellowish. Such leaves dropped off very readily. This 
