PEACH ROSETTE, AN INFECTIOUS MOSAIC* 
By J. A. McCuNTOcK 
Plant Physiologistf Georgia Agricultural Experiment Station 
HISTORY OF THE DISEASE 
According to Smith * peach rosette was first noted in Georgia in i88i. 
By 1891 this disease had been reported from 22 counties in Georgia, from 
South Carolina, and from Kansas, Rosette was also reported as occurring 
on plums in Georgia and Kansas, and on almonds in Kansas. 
Since 1903, reports of the presence of rosette have come to the Plant 
Disease Survey, of the United States Department of Agriculture, from 19 
oounties in Georgia, i county in Alabama, 5 counties in South Carolina, 
4 counties in Tennessee, i county in West Virginia, 19 counties in Mis¬ 
souri, and 2 counties in Oklahoma. These records indicate that for the 
past 40 years rosette has taken its toll of trees, and that it has spread 
over a considerable area. 
IDENTITY OF THE DISEASE 
In 1890-91, Smith ^ conducted experiments in middle Georgia in which 
he showed that peach rosette is an infectious disease. Of 125 seedlitig 
peach trees into which he inserted buds from a rosetted peach tree, 121 
developed rosette. 
In June, 1891, Smith® inoculated 37 Elberta peach trees with buds 
from a rosetted Kelsey plum. Two trees developed rosette and died in 
August, 1892. The other inoculated trees remained healthy. As a 
result of this experimmt Smith said : 
The small per cent of cases to unions makes it necessary to repeat this experiment 
before it can be stated positively that the plum disease is identical with that of the 
peach and transmissible tp it, as seems very probable from its appearance. 
In June, 1891, Smith ® inoculated 164 Marianna plum trees by inserting 
buds from rosetted peach trees. After i6 months not a single case erf 
rosette had developed bn the Marianna plums, so he concluded: 
There is, therefore, good reason to believe that the M^anna plum is not subject to 
this disease. 
In June, 1891, 12 Marianna plum trees were inoculated by Smith ^ 
with buds from a rosetted Kelsey plum. On final examination in Novem¬ 
ber, 1892, the‘Marianna plums showed no signs of rosette. 
The presence of rosette in orchards at the Georgia Experiment Station, 
and in a number of commercial orchards in various sections of the State 
led to further study of this disease by the writer, beginmng in 1919. As 
data presented by Smith ^ indicated that fungi and microscopic bacteria 
were not the cause of rosette, the writer did not attempt to repeat this 
phase of the work. 
^ Accepted for publication Aug. i8, 1922. 
* Smith, Erwin E. additionai, bvidbncb on thb communicability of pbach ybllows and pbacb 
ItosBTTB. FART H. PBACH ROSBTTB. In U. S. Dept. Agr, Div. Veg. Path. Bui. i. p. 4 S-S 4 ‘ *891. 
•Smith, Erwin F. thb peach rosbttb. In Jour. Mycol. v. 6, p, 143-148. pi. 8-13. 1891. 
• Smith, Erwin F. additional notes on peach rosbttb. In Jour. Mycol., v. 7. p. «26-a32. 1893. 
Journal of Agricultural Research, 
Washington, D. C. 
ado 
(307) 
Vol. XXIV, No. 4 
Apr. 28, 1923 
Key No. Ga.^ 
30618—23 - 3 
