452 
NOTES ON UROMYCES AMGYDALI, COOKE, 
Treatment." 
The treatment must be preventive, and sprayingwith ammoniacal 
solution of copper carbonate and modified eau celeste has been 
found successful in the United States. The improved form of 
Bordeaux Mixture, as given in Guides to Growers, No. 15 (see 
Literature at end), has been found effectual with us, and since the 
lower surface of the leaves is affected, the spraying should be 
specialty directed there. 
There is another preventive measure which should never be 
neglected, and that is the burning as far as possible of the 
affected leaves in order to destroy the winter spores. So important 
and so generally applicable is this advice, that the remarks of the 
late Baron von Thuemen on this particular disease may be quoted 
in full : — " The surest and most effectual means of combating this 
rust, as well as other rust fungi, is to destroy the resting-spore 
generation as far as possible. The purpose of the special spore 
appearing in the autumn is to tide the species over the winter. 
On the leaves lying on the ground, even if they are decayed and 
decomposed, the spore-clusters remain for the most part com- 
pletely safe. So when the trees put forth their young leaves next 
year they are infected afresh from the soil, by means of the spores 
present there in unlimited quantities, on little bits of the leaves 
hardly recognisable. These spores, on account of their tenacity 
of life, have received the name of ' resting-spores.' Hence the 
imperative necessity for the fruit grower to destroy the leaves 
covered with heaps of spores, in order to prevent fresh infection. 
This is best done in the autumn when all the leaves have fallen 
from the tree, and they may then be carefully collected and 
burnt. Or if this is impracticable, the land under the trees 
should be deeply dug so that all affected leaves may be buried 
deeply in the soil, where they can do no further mischief." 
Since writing this paper I have seen the Report of Professor 
Scribner* for 1887 on "Leaf Rust of the Cherry, Peach, Plum, 
* Report of the Commissioner of Agriculture, U.S.A., for 1887, pp. o53 
to 355. 
