The National tribune., 1882-07-29

PEACH-TREE YELLoWs.-The Michigan
Pathological Society has been discussing the
subject of yellows in peach trees, and have
arranged their conclusions in a series Of
formulas, which, although positively stated,
do not appear to add anything to previous
facts, and contain some very curious sug-
gestions. The conclusions reached may be
briefed as follows: 1.-The disease is con-
tagious; 1t did not originate in Michigan,
but was probably imported from its original
home, the peach region of New Jersey, Della
ware, and Maryland; neither soil nor Gull
ture is a factor in its spread; that all
varieties are subject to its attack; that it
may be communicated from tree to tree
by pruning-knife, shears, or saw; that no
remedy is known except to destroy the dis
eaSed trees promptly; that the burning of
the diseased trees may stop it entirely in an
orchard, and that nothing but a stringent
law for the destruction of the diseased trees
applicable to the whole State will prevent
the loss of every peach tree in the State"
We do not consider that these conclusions
are of much value, or that they are even
based upon facts. We have taken buds from
diseased trees in the orchard and set them
in healthy trees which were planted under
glass and the disease was not communicated
to the healthy tree. The States of New Jer-
sey, Delaware, and Maryland are no more
the original home of the disease than are
the States of Pennsylvania, New York, Ohio,
or Michigan. We consider that soil, cultiva-
ton, and climate are all factors in the origin
and spread of the disease. 1t is probably
true that no remedy is known that Will cure
diseased trees, although we have known
cases where diseased trees ultimately became
healthy, but these were under conditions
which could not be generally secured or
proftably applied. But perhaps the most
futile of the above conclusions is that which
advises the destruction OF all diseased trees
with the view Of stamping the disease out of
the State This would be akin to advising
the destruction of the population of a mala-
riOus district in order to stamp out the "fever
and ague;" the two cases are precisely alike;
they are both resulting from certain IN
healthy conditions Of soil and atmosphere
Killing off the population would certainly
diminish the number of cases of disease. but
1t would not remove the cause of disease.
Destroying diseased peach trees will not re-
move the causes which render the yelIows
possible; although it is wise thing to do.
because diseased peach tree is of no further
use, and 1t may communicate the disease to
others which are specially sensitive to &C
quire the malady through climatic or other
causes.
1t is a significant fact that yellows in
peach trees is not found in climates which
permit the full and healthy ripening of the
yearly growths of the tree. This disease
does not originate in districts where the
leaves of the peach tree go through the
gradual changes of color which indicates
approaching maturity III the fail of the year,
and when it's mission has been fulfilled the
foliage drops to the ground without being
prematurely precipitated by biting frOsts
Neither is it to be found on peach trees
which are cultivated under glass, even when
they are surrounded by orchards of diseased
trees, as we have had repeated occasion to
observe; and as already mentioned we have
seen the disease appear in three-year-old
trees which were transpIanted from an
orchard and planted under glass and after
wards disappear; the conditions for its
spread did not exist, and it was outgrown,
so to speak.
With facts such as these before us we need
not expect to remove the cause of yellows !
by simply removing the trees.