Reporter and farmer. [volume] (Webster, Day County, Dakota [S.D.]) 188?-1946, 1904-09-15
WHEAT RUST.
Continued from page A.

the wheat plant and IN a short time
they are able to project new red
rust or summer spores through the
surface of the plant in which they
grow. These red rust spores may
then in turn be blown to other wheat
plants, and SO on through the sum-
mer season. From these same
threads growing within the wheat
plant are produced late in the sea
son, or as the wheat is beginning to
ripen, masses of black spores. The
black spores, or winter spores, arise
from the same Sits in the surface of
the leaf or stem from which the red
rust spores arose, or may arise from
new Sits in the surface of the plant.
The black spores do not blow about
as do the red rust spores, as they
are fastened firmly to the threads of
rust in the wheat plant by short
stalks. These black or winter spores
do not in any 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 barberry
bushes. They do not infect barberry
bushes directly, but terminate upon
the old wheat stems where they are
formed, producing several small
spores, which may be blown to the
leaves of the barberry bushes,
thereby bringing about infection
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 barberry leaf enter the leaf
of the barberry and grow much the
same as in wheat. The lower sur
face of the barberry leaf is finally
broken and orange colored spores
are given off. The ruptures in the
barberry leaf, however, do not
appear like those of the wheat. They
take the shape of very small cups
and are grouped together in patches
upon the leaf. From their appear
ance 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.
Under the outer surface of the bar
berry leaf are formed 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 the cluster cups may be
blown from the barberry to the
wheat plant producing a new infec-
ton early in the season. These
infections of the wheat plant will in
turn produce the red rust or sum
mer 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 repre-
sents a life history which occurs in
Europe and many places in the
United States. 1t is doubtful, how
ever. that it is necessary for the
wheat rust to follow these stages in
the succession as given here, alter
mating from the wheat to the bar
berry and barberry to the wheat.
There are so few barberry bushes in
many parts of the United States
where the rust causes great damage
to wheat that it seems very improb-
BILE that the barberry is necessary
host for the cluster cup stage. 1t
may be that other plants besides
the barberry may serve as hosts for
this stage of the black stem rust. A
erect MANY ovnarimanfc have baan