Little Falls herald. [volume] (Little Falls, Morrison County, Minn.) 1889-1950, 1904-08-26
THE NATURE or RUST
Interesting Description Of
"a
the Plant Disease
the Remedy

SltyS OF North DAKOTA mas written an
Article on rust in wheat. which lie
generally regarded as the most ecienti.
&c and best presentation of the subject
yet made. The subject is at present
one of general interest, and we give
the, following extracts from Prof.
Bolley's article:
Cause-Rust on grain is caused by
d distinct plant which causes rust. is
microscopic In size. and grows from
spores, small seed like structures. It
is these which form the puetules or
rust spot, red, brown or black, seen
in masses. on the leaves, sheaths and
Stems of the grain. There are two
distinct species of rust which attack
wheat, both of which produce first red
spores, which make the red spots, and
later on produce the black spores
which turn those spots black color.
There is thus no such thing as red
rust, but rather the black rust is only
an advanced stage of the red which
precedes
Methods Of Rust Attacks and Rust
Growth-Red rust spores form first
in countless numoer and blow about
in the flightest breeze. II one falls
upon a wheat leaf or lodges against a
rough placs on wheat stalk, it re-
mains in resting &C ndition until a
light rain or slight dew fu;nish1s
film Of moisture upon the wheat,
when il terminates at once, sending
out small thread Of hliament. This
fliament bores its way into the stem
or leaf. The time necessary is but an
hour or two. Thousands of such spores
may often be counted IN al ordinary
dew drop, having fallen there from
the air as dust from other affected
plants. 1t takes from nine to thir-
teen days for the rust to break out as
a spot or pustule, after the germina-
tion of the injecting .spore. One can
tell WHETHER the wheat plant is in
fected or not seven or eight days be-
fore the real rust, the red powder,
which is made up Of spores, breaks
through the surface of the plant.
By examining the green straws or
leaves closely there may be seen slight
translucent or lemon yellow spots,
over much of the surface. Each such
spot represents point of. infection,
where the rust spore has terminated
and the 6liament has gone in. These
spots may best be observed by holding
the infected leaf or split piece of the
green stem between the eye and the
light.
Conditions Favorable to Rust
Growth and Destruction of the Crop
AS rust is due to the growth of a
plant upon and within the tissues Of
the wheat straw, naturally it must
have it's own peculiar conditions of
growth satisfied. There must be the
young terminating spores, proper
moisture, proper temperature, and the
right sort of food matter, or there
will be no outbreak Of rust. These
conditions may be called the primary
conditions which are necessary for the
development of rust. There are many
secondary which have favored rust
development. l have studied these
conditions some every year since 1887.
and this year especially.
So many elements of soil, water, and
plant growth enter the question that
it is confusing to attempt to explain
all of the noticeable conditions which
help to &C count for general rust de-
struction. We can however, summar-
ize few Of the most obvious condi-
lions which influence rust develop.
ment: ~ The straw of the crop
must be susceptl BILE to rust Infection,
that is to say must pe eoft or succu-
lent at the time the rust spores alight
npon it. To explain, some varieties of
wheat straw are more succulent,
more open to attack than others. All
at some' particular stage of growth or
maturity, Each variety is more open
to attack by rust just at the period
following healing time to the point of
the full blossom stage. II this period
of growth is prolonged by any soil or
weather conditions there is liability
of extensive rust infection. ~ The
wind mpsr be such as to bring to the
heading crop good supply of rust
spores. Great areas Of wheat may miss
destructive infection because Of spe-
cial conditions. The falling Of spores
and hence the local infection Of CIV
en- area may depend largely upon the
occurrence Of local rains or showers or
wind storme. As storms strike the
earth at other points, they pick up
and irregularly distribute spores from
which early outbreaks may OCCUR In
widely separated areas. Each new
local infection serves as a center for