PREVENTION AND CURE. 59 
dealing with methods for the control of the disease in the nursery, 
and the other with methods for its control in the orchard. 
METHODS FOR THE CONTROL OF THE DISEASE IN NURSERY BINS. 
Since it has been found that apple crown-gall is communicable, and 
can be transferred from the apple to the stone fruits, the raspberry, 
the blackberry, the rose, the grape, ete., and vice versa, nurserymen 
should at the time of digging pick out and remove all plants diseased 
with crown-gall. They should not be tied in bundles with other 
plants, owing to the slight possibility of transferring the disease to 
healthy wounded plants. In the case of apple-root grafts it has 
been shown that they are most susceptible at the time the graft is 
forming callus and is uniting. Care should be taken to keep the 
nursery bins, especially where material for root grafts is kept, free 
from diseased plants. It is best to clean all nursery bins and thor- 
oughly spray them with a strong solution of copper sulphate each 
_year before the time for storing trees for the winter. 
PROPAGATION OF SUSCEPTIBLE VARIETIES OF APPLE TREES BY 
BUDDING. 
It has been shown elsewhere in this bulletin that in most sections 
of the country where apple trees are propagated, both by budding 
and by root grafting, budded trees are freest from disease. For this 
reason it is advisable to propagate those trees most subject to crown- 
gall and woolly-knot by budding. There is an objection offered to 
budding on account of the necessity for growing the trees a year 
longer. The additional cost for this extra year may be more than 
offset by the increased number of healthy trees obtained by this 
method. The additional loss from woolly aphis during the last year 
of growth in the nursery is asserted by many nurserymen to be so 
great in some localities as to preclude budding. If such nurserymen 
will consult with the Bureau of Entomology of this Department as to 
the proper method of combating and controlling this troublesome 
insect pest by fumigation, etc., means will be found by which this loss 
may be greatly diminished, and propagation by budding in the case 
of varieties susceptible to crown-gall will become profitable. 
IMPROVEMENT IN METHODS OF ROOT GRAFTING. 
SELECTION OF HEALTHY SCIONS NECESSARY. 
In the control of any disease that might be transmitted through 
root grafts it is perfectly logical to demand that the pieces, both 
scion and root, that are built into the root grafts should be healthy. 
It has been shown on page 23 that there is an increase in disease due 
to taking apparently healthy scions from trees whose roots are dis- 
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