226 
Journal of A gricultural Research voi. xxv, no. s 
some of which will now be described, of similar types of local infection 
were met in connection with inoculations in the field which leave no 
doubt that “local” infections do take place when they occur at some 
point on a shoot several inches above the ground. 
Two shoots, No. 353 A and B of the Kittatinny variety, about 4 inches 
high, were sprayed with sporidia May 5, 1921. These grew into large canes 
5 feet tall and blossomed profusely in 1922, but no shoots, such as usually 
characterize infected plants, grew out from the lower parts of the canes 
during the spring. The fact that both plants had been slightly infected 
might easily have been overlooked. Each had been infected at a single 
node, and the fungus had failed to make any material advance upward or 
downward in the cane. The small branch of 353 A, was only partly 
infected; several blossoms appeared at the end. The parasite had at¬ 
tacked plant 353 B (PI. 3) somewhat more vigorously because all of the 
leaves of two small branches from the infected node showed the rust. 
Sections of the canes above and below the infected node would show no 
hyphae. These attacks were very limited in extent and could not have 
succeeded in permanently infecting the plant. Plate 3, A, show’s local 
infections in a Crystal White blackberry. 
Some very striking cases of localized primary infections of the wild dew¬ 
berry Rubus enslenii were noticed at Salem, N. C. Several plants showed 
rust only on leaves at one or two nodes; the rest of the vine in each case 
appeared to be perfectly normal. Longitudinal and transverse sections 
of the vines at about 2 inches above and below the infected nodes were 
made, but no trace of mycelium was found at these points. There can be 
no doubt that they were primary infections, and of a local nature, remind¬ 
ing one of the way the Calyptospora attacks the blueberry. The shoots 
from the infected nodes of these dewberries were very severely attacked. 
Rust pustules broke out along the young shoots, on the pedicels, and on the 
calyces as well as on the leaves. The conditions at the time they were 
infected must have been particularly suitable for the type which the 
writer calls localized gametophytic infections which fail to become 
perennial. The same spot was visited in May, 1923, and it was found 
that the rust had become established in only one of the plants. The 
shoots must have been rather well developed when the sporidia were 
being shed. 
In 1922 sporidia were sowed on a number of Taylor blackberries whose 
new canes were from 3 inches to 2% feet high. This variety proved to be 
very susceptible. The results indicate still more clearly that canes can be 
infected with the orange-rust even after they have reached a height of a 
foot or more. Eight of the canes that showed rust in the spring of 1923 
were infected at nodes now 18 inches to 2^ feet above the soil (PI. 5, B). 
In some canes the absence of hyphae in the internodes proved that sepa¬ 
rate infections had occurred at adjacent nodes. It will be shown later* 
that had these plants been grown in flats in a greenhouse, the mycelium 
would have spread pretty generally through the canes and into the roots 
because of the conditions which contribute toward etiolation and thus 
prevent the canes from entering the dormant condition until later. A 
vine of the dewberry, Rubus hispidus , was found infected at only one 
node. No mycelium was seen in sections of the adjacent internodes. 
Cutting away the infected node freed the plant entirely. It has grown 
two years since without showing rust. 
