The herald-advance. (Milbank, S.D.) 1890-1922, 1904-09-16

NV ~AS
way that is known infect other wheat
plants. They have been known.
however, to live through the winter
and bring about infection the next
year on Burberry bushes. They do
not infect Burberry bushes directly,
but terminate upon the old wheat
stems where they are formed, produc-
ing several small spores, which may
be blown to the leaves of the Burberry
bushes, thereby bringing about infec-
ton much the same as the red rust
spores bring about infection upon
the wheat plant. The threads of the
rust arising from this infection on the
Burberry leaf enter the leaf of the
Barberry and grow much the same as
in wheat. The lower surface of the
Burberry leaf is finally broken and
orange cOlOred spores are given off.
The ruptures in the Burberry leaf,
however do not appear like those of
the wheat. They take the shape of
very small cups and are grouped to-
gether in patches upon the leaf. From
their appearance upon the leaf of the
Barberry this stage is spoken OF
as the cluster cup stage of the rust.
From these small cups are produced
chains of spores. AS the Oldest
spores at the outer ends of the
chains are given off, young spores are
formed at the opposite end. In this
way great numbers of spores can be
distributed from these cups in a short
time. Upon the other surface of the
BarDerry leaf are found slight struc-
lures, producing spore-like bodies, the
function of which has not yet been
discovered. 1t is probable that these
spOre-like bodies perform no necessary
office in the life history of the rust as
it exists today. The spores from fhe
cluster cups may be blown from the
Burberry to the wheat plant. produc-
ing a new infection early in the sea-
son. These infections OF the wheat
plant will in turn produce the red
rust or summer spores, and later in
the season the black rust or winter
spores.
These facts represent the round of
the life history of the black rust in
wheat as it has been worked out by
European investigators and verified
by some American investigators.
There is no doubt that this represents
a life history which occurs in Europe
and many places in the United States.
1t is doubtful. however, that it is
for the wheat rust to follow
these stages in the succession as
given here, alternating from the wheat
to the Burberry and Burberry to the
wheat. There are SO few Burberry
bushes in many parts of the Uuited
States where the rust causes great
to wheat that it seems very
hat the Burberry is a
host for the cluster cup
stage. 1t may be that other plants
besides the Burberry may serve as
hosts for this stage of the black stem
A great many experiments have
tried in in Getting wheat from
cluster-spores OF other plants besides
the Burberry, but o M of these have
as yet been known to produce the
black stem rust of wheat.
1t is probable also that the wheat
plants in warmer climates may con
the red rust spOre production
throughout h winter season, thus
making the Burberry stage an I'M
stage to the continuance of
the rust from year to year. Where
winter wheat is grown in warmer eli
mates it may be that the threads of
the rust in the leaves or stem of the
wheat plant live through the winter
and produce red ruSt spores the fol-
season. In cold or temperate
climates experimenters have been un-
able as yet to demonstrate this.
From "a careful study of the neces-
sary facts in the life history of wheat
rust, as given here, several points may
be deducted:
l. The condition of the weather for
weeks following the first in
lection of the wheat is one of the most
factors in causing a very
extensive distribution or epidemic of
rust. There are very few if any
seasons in which no rust can be
found upon the wheat. The extent of
distribution, however, is probably
very largely or almost entirely due to
weather or soil conditions existing
during the period of rapid growth OF
wheat. Warm: moist weather, with
neavy dews and fogs, is favorable to
termination of the red rust spores.
breezes are of course necessary
the distribution of the red rust
spores. In South Dakota it is very
that there is not futficient wind
10 distribute the spores far and wide.
Dry winds coming at the right time
and continuing for several days
check the distribution and
spread the rust. 1t will be seen,
then, that the weather, though not the
cause of rust, is probably
The most important factor in making it
epidemic. Professor Bolley, of the
Dakota Station, considers that
poor drainage of the soil is also one
Of the important facts in favoring
the development of rust. Excessive
of nitrogenous.fertilizers
to the soil. or anything which favors
The production of a succulent growth
Of the wheat plant, tends to make it
susceptible to attacks of rust.
1t is not at all strange that before the
life history of the rusts were known
he weather was. considered the only
Statements that the sun breaks
open the surface of the leaf and that
he red and black formations are caus-
I'd by the sap exuding from these Sits
are of course erroneous.