Devils Lake inter-ocean. (Devils Lake, Ramsey Co., Dakota [N.D.]) 1884-1905, 1905-05-05
Scientific il Study
OF Wheat Rust

M AASG1G ANGAoG
For a number Of years it has
been the belief Of the writer that
1.-The efficiency Of the uredospores
(sumnner spores) of wheat rust
Ito perpetuate the disease is pos
sibly much greater than thought
| to be. 1t has been assumed by
most botanists that those spores
lare quick to terminate and short
1of life. As there are formed
definite resting spores of and
also the cluster cup stage on the
barberry bush, it has been APP
Eparently taken for granted that
i the summer spores have no
other effect than to rapidly
spread the disease from plant
to plant during the summer sea
son. 81.
1t will be interesting news to
Imycologists to know that we
Ihave at last definitely establish
| ed the fact Of the wintering of
| the red spores (uredo spores)
Iof a number of the important
trusts in visible form, including
1.-THE important species Puccinia
graminis.
n During the winter of 1883 and
n 1889 the writer, while working
at the Indian Station, first de-
monstrated the fact that the.
1 myceliurn Of the uredo stage,
\ red spore stage, Of the species
i known as Puccinia rubigovera
would pass the winter in the
tissues Of the wheat plant unin-
Ijured. (See Agricultural Science
IVol. 3, page los. During the
summer:of 1890 (See Agricultur-
Ial Science Vol. 5, Nos. IL, and
ID it was further proved that
1 the red spores Of this last named
species could survive exposure to
1.-THE drying air and sunshine Of
July and August for over a
month. This indicated that it
/ was possible for such spores to
aIbe borne many miles by the
wind, and aided to an unde err
standing of the rapidity with
(which general rust infection may
take place over large areas Of
Icountry.
Aided by the persistent and
/ lpainstaking efforts Of assistant
Plant Pathologist, Mr.. F. ].
Pritchard ] have at last been
4 able to make numerous trial
studies upon methods Of storing
1 land keeping wheat and other
TYPES Of grain straw which is
] infected by red rust so as to
carry out various studies upon
A the most successful methods Of
testing the vitality of the spores
4 from week to week and from
4 month to month. We are now
q liable to announce definitely that
j 1.-THE vitality Of the red spores
! (uredo spores of Puccinian era.
minis remains unimpaired by
the action Of the drying WING
lof autumn and the intense cole
. Of a North Dakota winter. II
some cases we have been able Il
terminate as high as 80 to 81
4 per cent Of all the spores unde
4 test. We have found these spore
y successfully surviving upon dea,
j leaves, dead straw and upon tn
partially dead or green Leaves
4 Of living grain or grasses. Tni
applies also to a number Of orhe
q important rusts which attacl
j wheat and allied grasses.
. In the case Puccinia rubigo
a vera, the smaller wheat rust,
Z has been found by the writer !,
j be Wintering freely in Missipp
VI Texas. Illinois, Minnesota an,
II North Dakota both upon Twin,
leaves Of wheat or winter ny,
I and upon the lnatured leaves an,
straw Of the same. This fac
\ will Of necessity have grea
i weight upon the future inVesti
y cations of wheat rust. The mat
X ter Of the barberry stage an,
other aecidial rasts may yet b
proved to- be of physiological
Il aeessity for the parpetutaIiol
DE the species. but il wo lid seen
Althat these need no longer be be
q llieved to be d direct yearly nee
essitY to the perpetu atiaT1 81
I the rllsts concerned Prof. Boil
. in North Dakota Farmer.
May atel