CHERRY DISEASES 
early in the history of fruit raising in 
the Northwest. 
It is not known to what extent the 
cherry industry in other parts of the 
United States suffers from the presence 
of gummosis. Little is heard from it in 
the drier, eastern portion of the North- 
west; but in the moist valleys of Wash- 
ington and Oregon, west of the Cascades, 
at least, the trouble now reaches such 
proportions as to dishearten many cherry 
growers and discourage other orchardists 
from planting cherries. The conditions 
demand a thorough investigation as to 
the causes, means of prevention and pos- 
sible remedies. 
Various Causes of Cherry Gummosis 
As has been intimated, the formation 
and exudation of gum is to be considered 
as the result of an injured, diseased or 
otherwise abnormal condition of the tree. 
It is a symptom only and not the disease 
itself. The published literature on cherry 
gummosis brings to light many explana- 
tions for the appearance of this phenom- 
enon, some well proved and others more 
or less theoretical. 
Injuries 
Mechanical injuries, such as bruises, 
may induce the formation of gum, but 
the wound usually heals quickly and the 
gumming ceases. The injection of certain 
chemicals into cherry trees has repeated- 
ly caused gum flow, and such insects as 
borers may produce it; but these causes 
need not engage our attention. 
Unfavorable Soil and Climatic Conditions 
A. disturbed or disordered physiological 
condition of the tree, produced by un- 
suitable soil, moisture, climate or other 
relations not perfectly understood, is un- 
doubtedly an important factor and pos- 
sibly even a primary cause in many cases 
of gummosis. It is often noticeable that 
trees set in low places, where excessive 
moisture is likely to be present, are more 
apt to be subject to the disease than those 
on better drained ground. But this can- 
not explain all, since some trees under 
the best of soil and moisture conditions 
are severely attacked. Gumming seems to 
be worse where soils or subsoils are poor 
781 
or unfit. But may not a weakened con- 
dition of the trees due to such causes 
render them less resistant to definite dis- 
eases? Many good authorities in this 
country and Europe attribute to late 
frosts following warm spells many at- 
tacks of this trouble. Some methods of 
pruning and cultivation have also been 
held responsible for a certain amount of 
gummosis. While all these factors have, 
no doubt, some influence on gum-produc- 
tion, yet investigation reveals so many 
cases inconsistent with these explanations 
that we must look for other possible 
causes. 
The Attacks of Fungi 
Since the outbreak of a serious cherry 
disease in Germany in 1899 various bark- 
destroying fungi have been found asso- 
ciated with the disease. From observa- 
tions up to the present it does not seem 
very probable that any of these are re- 
sponsible for more than a small amount 
of injury to living trees in the Northwest. 
It is possible, however, that they play a 
more important role than has been sus- 
pected. 
There also appear frequently on the 
trunks and limbs of dead or diseased 
cherry trees certain fungi of the wood- 
rotting types. Being found not infre- 
quently on trees that are not totally dead, 
they have been suspected by some of hav- 
ing a hand in extending the diseased con- 
dition. It is not known, however, that 
these fungi have anything directly to do 
with the disease in question. 
Description of the Disease 
Numerous distinctly different troubles 
of the cherry may be accompanied by 
gum-production, hence, the term “cherry 
summosis” should not be applied to any 
specific disease. It is my present opinion, 
however, that the greater part of the 
cherry trouble in the Northwest is due 
to a single disease appearing in a variety 
of forms between which there are hardly 
distinguishable gradations. 
The More Serious Phases of the Disease 
The condition most dreaded is where 
trunk and limbs are quite generally at- 
tacked. This may appear at its worst 
