Shenandoah herald. [volume] (Woodstock, Va.) 1865-1974, 1911-05-05
WILL TELL. OF RUST.

At the request of The Winchester
Star, Prof. J. s. Cooley, assistant in
plant pathology of the Virginia Agri-
cultural Experiment Station, OF
Blacksburg, who is now doing some
special work at the Mlddletown Agri-
cultural High school has prepared an
article on the cedar rust which has
cost the fruit men a great deal OF
money during the past few years.
Prof. Cooley says:
ITO many it seems very queer that
the innocent looking cedar that is so
different from the apple should be the
cause of such enormous losses to the
fruit growers of the Valley. In many
places the so-called orange rust or
cedar rust is SO destructive that GER
tain varieties have failed to yield any
marketable fruit.
Since / have been asked to write on
the life history, and since one Can
more intelligently combat disease
when he knows the life histo@v OF the
causative fungus, it is my purpose to
give a brief discussion of the life his
tory of the fungus causing the disease
COMMONLY known as orange rast or
ceiarsnst or Little York. -
The fungus, like many other mem
bers of the rust group, seems to like
variety, for it lives on the cedar dur
ing one stage of its growth and on the
apple during the other. Suppose we
begin with the stage found on the
cedar. During the past several trains
(since April 81 we have noticed more
or less of the cedar apples in bloom,
as we call it, When the blOssoming
cedar apple is examined, we observe
number of gelatinous strings or
tentacles one-half inch or more in
length. These gummy strings we find
by II icroscopic examination are com
posed of numbers of spores spores
correspond to seeds). Burning the
warm rains of spring these spores in
the cedar apple produce four or eight
very small spores. Now, these little
spores are blown from the cedar to
the apple leaves, where they germinate
and grow into the leaf or fruit. Many
of these little spores have formed on
the cedar apple at the present time,
AMI are ready to infect the apple
leaves. The first indication of the
disease on the apple leaf is the pale
yellow SPOT on the upper side Of the
eaf' which is followed by a thickened
cluster cup on the under side of the
leaf. The sporee from this cluster
cup, strange to say, infect the cedar
and those from the cedar in turn in
feet the apple.
Other apple diseases live over win
ter in dead leaves or mummied fruits
or cankers on the trees, but this rust
fungus, so far as we know at present,
| can winter only on cedar trees.
If you have had the rust in your
orchard other years and have not YET
removed the cedars, be sure to use
lime-sulphur or Bordeaux in your
sprays for the Goblin G moth that you
give now after the petals fall and
! again in two or three weeks. But the
surest and best way, where practicable
is to cut down all red cedars within
one-half mile of the orchard.
The Virginia Agricultural Expert
ment Station has placed me here al
Middletown to conduct some field and
laboratory experiments GU the cedar
rust. l will be glad to explain the
experiments to any one wishing to
look them over or to be of any assis-
lance possible to the fruit growers.
JACQUELIN S. COOLEY,
Assistant Plant Pathologist.