58 THE CROWN-GALL AND HAIRY-ROOT OF THE APPLE TREE. 
PREVENTION AND CURE. 
PROBABLE FUTILITY OF ATTEMPTS AT PREVENTION. 
Numerous recommendations have been made from time to time 
by plant pathologists and others looking toward the prevention of 
crown-gall by the removal of supposed sources of infection. These 
recommendations were made not specifically for the apple disease but 
for crown-gall in general. Advice has generally been given to obtain 
nursery trees as far as possible from nurseries free from disease. It 
has generally been considered that the planting of trees affected with 
crown-gall and hairy-root is liable to give rise to diseased trees 
throughout the orchard. In spite of the most vigorous nursery 
inspection for a number of years in many States the disease on apple 
trees is quite generally disseminated throughout the United States, 
and the writer knows of no apple-growing nursery that is entirely free 
from the forms of disease described in this bulletin. 
Although much advice has been given for the prevention of the 
disease, little in the way of successful experimentation along this line 
has been done hitherto. Butz (7) planted healthy trees in infected 
land to which finely powdered sulphate of copper had been added. 
On account of the death of most of the trees, attributed to a serious 
drought, he was unable to make any generalization regarding the 
efficiency of this treatment. Sulphur used by him in the same way 
had no effect in retarding the disease. 
Popenoe (45), in speaking of attempts made by growers in Kansas 
to prevent loss by apple crown-gall, says: 
It has been the hope of some nurserymen to prevent the large percentage of loss 
from diseased stock by planting their apple grafts in localities and soil not before 
in apple trees, but in some notable cases coming under my observation within the 
last few years this endeavor has failed signally of the object. 
The writer personally knows of similar experiences by nurserymen 
in a number of localities in Kansas, Nebraska, Missouri, and Iowa. 
The writer has conducted a number of experiments along the line 
of prevention and cure. Some of these have resulted in materially 
lessening the amount of disease present in nursery stock. The results 
will be given, in the hope that they will effect a great saving not only 
to nurseymen.but to orchardists as well. 
As a result of many observations in nearly three-fourths of the 
States in the Union the writer is of the opinion that the crown-gall 
organism is so widely disseminated that any system of eradication 
must fail. 
In discussing methods to control and limit the formation of crown- 
gall and hairy-root on apple trees in nurseries and orchards, the 
the subject-matter will be brought under two general headings, one 
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