The Prince George's enquirer and southern Maryland advertiser. (Upper Marlborough, Md.) 1882-1925, 1902-06-06
PEACH ROT.
BY J. b. 5. NORTON, STATE PATIIOLoGIST

The rOttlng OF the 1rult causes 4
greater loss to peach growers in Mary
land than any other disease. Last
year. on account of the weather condi-
tions favorable to the development Of
the rot fungus, there was an eNccp-
tional loss; and it is very probable
that with similar weather conditions
this year, with the large amount OF
rotted fruit now present in orchards, 4
still greater loss from the rot would
result, if something is not done to con-
troll it. Last year the loss was in
some places as much as half crop.
The result OF a careful and conser-
vative estimate of the loss from the
Brown Rot in one year in the Mary
lrnd and Delaware Peninsula was
100000.
The rot is caused by 4 fungus. Mo-
niHo ,truct;yinin, whose minute thread
like growth rapidly permcatcs the It's
sue OF the peach and causes the rot.
The dusty powdcry substance pro
duccd III lie a~'' '",nr''' spots or
patches ON the outside OF the rotten
peaches consists of thousands of spores
of the fungus, each so small that it
cannot be seen without Il microscope.
Most of these spores. if they have pro-
per conditions. would grow and pro
ducc the rot in other placet. The
fungus develops very rapidly in warm,
wet weather. The most favorable time
for its growth in the peach is at the
time of blossomiDg and about the ri
pening period The rottcd fruits usu-
ally shrivel up, and many hang on the
trees over winter.
Some of the spores may live and
develop after several years, but the
fungus is carried over winter mainly
10y the live portions remaining in the
dried up or mummy peaches, which
hang on the trees or lie under them
Early i'll spring, in warm moist wealth
er, countless spores are produced from
these mummy fruits, and, carried by
winl or water, may develop in the
flowers. causing them to turn brown
and die, as if struck by frost. Later
on it attacks the fruit, and from dis
eased fruit or nowcrs may pass down
ward and kill many OF the twigs. The
inner part Of trees in Il season tarora-
Die to rot are often filed with these
bli2hted twiLs. The same Iungns also
attacks plums and cherries.
1t is clear that il the livin. portions
of the fungus can be destroyed, AID
the spores, since ly means Of these on
ly the rot spreads, prevented from
terminating on the fruit or other suS
ceptible parts OF the tree, the rot will
he prevented, no matter what the
weather. Any means o, reducing the
moisture on The tree or fruit would
also help to control it, 1t is very i'm
probable that orchards could be en-
tircIy freed from rot, bat experience
shows that it can be controlled to Il
very profitable extent. United efforts
on the part of ncighboGs " 'uld ',"in
better results to each than if only III.
occasional one should treat his own
orchard Successful control Of the rot
this year will mean, with the same
conditions, less rot next year.
Better orchard management will
help to control the rot. Avoid low,
damp situations tor the orchard, and
prune trees so as to admit air and sun
shine The moisture enclosed in close
headed trees makes decided differ
ence in the amount of rot. In prun-
ing, the twigs killed by the rot fungus
should be removed.
In early spring, all the dried up
peaches remaining on the trees or un
der them should be collected and eth
er blrnrd or buried. They mry be
rakcd out between the rows and pow
ed under so deeply that cultivation
later in the spring or summer will not
unealth them. The reproducing
spores may, however. develop from
them, if they are again turned up the
following year In destroying these
mummy fruits, the principal source of
infection is removed.
Thorough spraying with some fun
gicdc to prevent the growth from
spores that may be present on the
tree or the sound lrlit will control the
rot. In spraying, the following pro-
cedure is advised: Spray before the
buds begin to swell with Bordeaux
mixture, made at the rate of four
pounds copper sulphate and six pounds
of good quick lime to fifty gallons of
water. After the fruit is set spray
with the Bordeaux mixture made with
three pounds Of copper sulphatc and
nine pounds of lime to fifty gallons of
water. This spray should be repeated
some time in the summer, certainly, if
rot begins to appear. If, however, a
spray must be applied inside of three
or four weeks Of ripening time, cop
per acetate, or copper carbonate spray,
that will not discolor the fruit, should
be used If conditions make it impos-
sibe to give but two spray ings, spray
before the buds begin to swell, with
copper sulphatc solution or strong