Journal of Agricultural Research 
Vol. XXIV, No. 4 
310 
the Damson plum branch. The diseased peach buds started growth 
within two weeks, producing typical rosetted shoots, but with somewhat 
larger leaves and more intemodal growth than did similar rosetted buds 
on the diseased peach stock from which the buds were taken. During 
the summer of 1920, the plum buds just below the place where the peach 
buds were inserted, developed small rosettes of mottled leaves (PI. 4, A) 
indicating that the causal entity had passed from the diseased peach 
buds into the healthy Damson plum branch. None of the branches of 
the peach stock on which the plum was budded showed symptoms of 
rosette during the summer of 1920. The growth of the peach stock was 
so vigorous that a small copper wire, by which a label had been attached 
to the trunk in 1919, became embedded in the tissues of the stock, a few 
inches above the point where the Damson plum bud was inserted. In the 
spring of 1921, rosette developed in all growth of the Damson plum 
branch, and in all branches of the peach stock which grew from the trunk 
at points below where the copper wire was embedded in the tissues. 
None of these rosetted branches set fruit, though a few produced weak 
blossoms. All of the branches which grew from the trunk above where 
the wire was embedded produced normal leaves and blossoms which set 
numerous fruits. By July, 1921, the leaves on this tree began to wither, 
and by August 20 the tree was practically dead (PI. 4, B). No symp¬ 
toms of rosette appeared on the tree above the embedded wire, and the 
leaves and fruits shriveled and clung to these branches for some time 
after the tree was dead. The fact that no symptoms of rosette appeared 
above the embedded wire supplies additional data as to the tissues 
through which the causal entity progresses, and is being further investi¬ 
gated. 
In this experiment rosette was transferred from the peach to the plum, 
and back to the! peach, indicating that peach and plum rosette are iden¬ 
tical. 
Rosette has also been transferred from peach to Red June plum by 
means of infected buds. 
PEACH to winn PEUM to peach 
Experiment 6.—On September 22, 1920, buds from a rosetted May¬ 
flower peach, 7 years old, which developed as a natural infection in one 
of the station orchards in the spring of 1920, were put in two wild 
Chickasaw plum trees, growing in a fence row on the station. These 
buds remained dormant until the spring of 1921, when both the peach 
buds and the plum stock developed rosetted shoots. The inoculated 
plums (PI. 4, C) grew more slowly than the surrounding healthy plum 
trees during the summer of 1921. The appearance of the rosetted wild 
plum is not so striking as that of a rosetted peach, because the plum is 
naturally of dwarfed growth. The wild plum, being of no economic 
importance, grows in waste places without coming under the close obser¬ 
vation of man; therefore one or more rosetted wild plum trees might 
easily be an unobserved source of infestation to surrounding orchards. 
On May 23, 1921, buds from the rosetted wild Chickasaw plum were 
inserted in the new growth of a 2-year-old seedling peach. During the 
summer one of these plum buds produced a rosetted shoot about an 
inch in length, but no symptoms of rosette appeared in the peach stock 
up to the time it was defoliated by frost. In the spring of 1922 this 
