786 
the body of the tree, or to indicate just 
what part they play in its spread. The 
possibility of their being causative agents 
seems, however, to receive considerable 
support from the recent. investigations. 
Experiments must be carried on over a 
number of years before the nature of the 
disease can be demonstrated .beyond a 
doubt, or recommendations for its control 
can be made with assurance. The rela- 
tion which climatic and soil conditions, 
the attacks of insects or fungi, and the 
methods of cultivation have to the dis- 
ease, must be studied thoroughly. This 
will take time and the cherry grower 
must not be impatient. 
Prevention and Control 
More important in the eyes of the prac- 
tical orchardist than the cause, is the 
remedy for the disease. 
Resistant Stocks and Varieties 
The Mazzard Cherry as a Stock 
Attention has been called to the fact 
that winter injury and unfavorable soil 
conditions may have a great deal to do 
with the appearance of gummosis in the 
cherry. It may be that the more serious 
phases of the disease cannot occur with- 
out a previous injury or weakened vital- 
ity due to some such factors. It is well 
known, both in this country and abroad, 
that the so-called Black Mazzard cherry 
is generally much hardier and less liable 
to suffer from adverse conditions than 
are the cultivated varieties. Hence, seed- 
ling Mazzards have come to be much used 
in Europe as stocks upon which to graft 
the commercial sweet varieties. In this 
country also the Mazzard is coming to 
be recognized as a sturdy stock which 
unites with the sweet cherries better than 
the Mahaleb. <A point in favor of the 
Mazzard as a stock is that it seldom 
“oums.” To make use of Mazzard stock 
and to graft or bud on the limbs the vari- 
ety desired, gives trunk, crotch and limb 
bases that are practically free from 
trouble. If the disease then appears in 
the top, it cannot involve the entire tree 
and experience seems to show that the 
branches are much less liable to suffer 
from gumming when the body of the tree 
is clean. 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
Fig. 6. The Results of Artificial Inoculation 
with Ps. Cerasus. (O) Indicates an inocu- 
lation. (X) A check puncture with sterile 
needle. <A. Blighting of inoculated spurs. 
Checks opening normally. B. Gum exuding 
at points of inoculation on the body of two- 
year-old tree. The check punctures healed. 
Examination of orchards aggregating 
some thousand trees supposed or known 
to be top-grafted upon Mazzard stocks 
showed 80 to 91 per cent free from any 
indication of disease on the trunks where 
orchards not upon this stock were found, 
to have, in some case, over 60 per cent 
and in one case over 80 per cent of the 
trunks badly cankered or killed by the 
disease. The writer is convinced that 
the use of the Mazzard as a stock on 
which to limb-graft or bud the other 
varieties, is a thoroughly practical way 
