The Black Hills union and western stock review. [volume] (Rapid City, S.D.) 1904-19??, 1904-10-14

RuSt on grain is caused Dy QlStIHCl
plant parasite. 1t is microscopic in size.
and grows from spores. 1t Is these
which form the postules or rust spots,
red, brown or black, seen en- masse, 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 pro-
duce the black spores which turn those
spots a black color There is thus no
such thing as red rust and black rust.
but rather the black rust is only an ad-
vanced stage of the red which pre-
cedes, writes Mr.. H. L. Bolley in the
Orange Judd Farmer
Red rust spores form first in count
less numbers and blow about in the
slightest breeze. If one falls upon
wheat leaf or lodges against rough
place on a wheat stalk. 1t remains in
sorting condition until light rain or
slight dew furnishes a film # moisture
upon the wheat. when it terminates a
once. sending out a small thread or fill
| ament. This filament bores it's way into
the stem or leaf. The time necessary Is
spores may often be counted in an or
binary dew drop. having fallen there
from the air as dust from other affected
plants. 1t takes from nine to IL days
for the rust to break out as spot or
pustule. after the termination of the
injecting spore. One can tell whether
the wheat plant is affected or NOT
seven or eight days before 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 yell
low spots over much of the surface.
Each such spot represents a point of
| infection, where a rust spore has ger
minated and the flament 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.
| AS rust is due to the growth of a
plant upon and within the tissues of
the wheat straw. naturally il must
have it's own peculiar conditions of
growth satisfied. There must be the
young terminating spores. prope, mois-
| ture, 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 ones
! which favor rust development. I have
studied these conditions some every
year since 1887. and this year especially.
I have made many examinations in
more than one-half Of the counties of
|
ton to all such features as by nbserva-
| ton seemed to directly influence the
early development of rust or alow it to
specially destroy the grain.
| 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 account for general rust destruction.
| One cannot make general assertions
which are fully applicable to great
area like the state of North Dakota.
We can, however. summarize few of
| the most obvious conditions which in
huence rust development.
The straw Of the crop must be Sus-
! ceptible to rust infection. that is to say
must be soft or succulent at the time
the rust spores alght upon it. To eX-
plain, some varieties of wheat straw
are soft, more succulent, more open to
attack than others. All varieties are
! more or less susceptible at some par
| ticular stage of growth or maturity.
| Each variety is more open to attack by
rust just at the period following head
| ing time to the point Of the full blossom
| stage. If this period of growth is pro-
longed by any soil or weather condi-
tons there is liability of extensive rust
| Infection.
The wind must be such as to bring to
the heading crop a good supply of rust
! spores. So far as North Dakota is con-
cerned the chief source of rust spores
| lies to the southeastward. thus the
| southeast winds are the chief carriers
of rust spores, and these spores gener
ally come from field to field. though
there may be nothing regular about the
| order of infection. Great areas of wheat
may miss destructive infection because
| of specian conditions. The falling of
spores and hence the local infection Of
| a given area may depend largely upon
| the occurrence Of local rains or show
NrytrN Il {ot> f,>slr
the earth, rebound and return to the
earth at other points. they pick up and
irregularly distribute spores, from
which early outbreaks may occur in
widely separated areas. Each new To-
cal infection serves as a center for the
later general infections.
The elements of moisture and tenn
perature are most confusing. These
must be right during the blossom and
milk stage or there can be no general
rust infection or great destruction fol-
| lowing. Each of these conditions may
deed, must vary widely during the pc
Rod of development mentioned. The
most effective rust infection weather
may be described as muggy, showery,
sultry, rather than hot days. with foggy.
COOL dewy nights, at about the blossom
period. Following the infection. cool
moist, slow growing, showery weather
may result in the most general rust in
lection, and In the greatest breaking
out or rupturing of the straw. Then
the greatest destruction of such crop
will follow If hot. drying days prevail.
just following the outbreak.
Dry, clear, windy weather following
the milk stage will tend to hasten ma
turity and harden the straws. Such
weather thus lessons the possibility of
great rust development on the inside
of the straws. Any feature of soil or
climate which gives the crop rapid ma
turing conditions tends to save 1t from
rust destruction. If an abundant crop
of black spores appear on the straws
| or the heads before maturity, one may
know that there win be very poorly
filled grain and great destruction, in
some cases even complete destruction
of the crop. The cause Of this destruc-
ton is based on the fact that the inter-
nal development Of the parasite had
been extensive. and plant foods which
and head have been used up by the
parasite. The straws have also been
perforated or ruptured, so that mois-
ture escapes very rapidly and they
weaken and crinl1le over.
Aside from the three general points
just mentioned many local conditions
influence the vigor Of rust attack
These cannot be stated so definitely.
They vary with the influence of the
greater factors. The most important
Of these local features are soil fertility,
soil texture, mechanical condition OF the
soil and drainage conditions
One cannot make a general asser-
ton covering these features or even
any particular one which will hold true
for all OF the different soil areas of the
state. Thus. in one type of soil. low
lying areas In the fields will show the
first and most destructive development
Iof the rust. In another. the highest
4 and driest lying areas are found to be
first and hardest hit. The general OBJ
seryation which seems applicable to ali
regions of the state may be stated as