314 
Journal of Agricultural Research 
Vol. XXIV, No. 4 
One of the Bitter almond buds had produced a much branched shoot 
about 16 inches long by June i, 1922, the leaves of which were more 
tufted in growth than those of healthy Bitter almonds. The peach 
shoots which grew from the stock below the point of inoculation had 
developed an upward rolling of their older leaves and most of the lateral 
buds had produced small rosettes of yellowish green leaves (PI. 10, B). 
The Texas Seedling almond buds remained dormant and up to June, 
1922, the peach stock into which they were inserted had shown no 
symptoms of rosette. Peach seedlings budded to healthy almonds have 
remained healthy up to June i, 1922. 
This, together with the foregoing experiments, indicates that peach, 
apricot, plum, and almond are susceptible to rosette and that in all 
cases the causal entity is the same. 
soil. TRANSMISSION OF ROSETTE 
Experiment 14.—Natural infection of rosette has been observed by 
the writer in Georgia on peach trees from 2 to 8 years of age. Where 
rosette develops in an orchard of young trees the question arises as to 
the advisability of setting a healthy tree in the place from which a dis¬ 
eased tree has been removed. It has been proved by Smith ® that infec¬ 
tion may be produced through inoculation of peach roots, so it seemed 
advisable therefore to test soil transmission. 
Two 6-year-old peach trees, which had developed rosette in the 
spring of 1919, were dug up September 5 of the same year and removed 
from the orchard. Early in January, 1920, a healthy i-year-old peach 
tree on peach stock was set in each hole. No attempt was made to re¬ 
move fragments of roots left from the rosetted trees. The two trans¬ 
planted trees made satisfactory growth during the summers of 1920 
and 1921 showing no symptoms of rosette. This, indicates that one 
may safely set a healthy tree in a place from which a rosetted tree has 
been removed. 
THE TRANSMISSION OF ROSETTE BY MEANS OF SAP FROM DISEASED 
TREES 
In rosette of the several species of Prunus there is a shortening of 
intemodal growth and in some cases mottling of the leaves similar to 
mosaic diseases of vegetable and field crops. Numerous inoculations 
have been made in various parts of susceptible species of Prunus using 
methods known to be successful in transmitting mosaics of other plants. 
In no case has rosette been produced by transfers of sap from rosetted to 
healthy trees, but experiments along this line are being continued. The 
results obtained thus far confirm data presented by Smith® to the effect 
that under artificial conditions rosette is transmitted only when an 
organic union takes place between infected tissues, and tissues of a sus¬ 
ceptible host. Thus in experiments conducted to date, rosette differs 
from other mosaics in the method of artificial transmission, indicating 
that the causal entity is somewhat different from that of other mosaics. 
» Smith, Erwin F. additional notes on peach rosette. In Jour. MycoL, v. 7, p. 226 - 232 , 1893. 
•Smith. Erwin F. the peach rosette. In Jour. MycoL, v. 6, p. 143-148, pi. 8-13. 1891. 
