The Meridian times. (Meridian, Idaho) 1909-1938, 1916-12-15

somewhat complex. There can be nc
doubt that the grasses have marked
influence on the prevalence of rust
and that wheat rust epidemics are con
siderably promoted by the common
wild grasses. The different rusts are
found, however, only on certain kinds
of grasses and these relationships, to-
| gether with the possible effect of the
grasses on the virulence of an cpl.
demic, are now being investigated.
Rusted Seed.
Another extremely important ques-
ton under investigation is that OF
rust in the seed. 1t has been known
for some time that In badly-rusted
fields the rust If often present even
on the tips of the wheat seeds. 1t has
been thought by some that this rust
might be transmitted by the seed to the
young Seeding and thus start the cpl
demic again in the following spring.
Evidence from field and greenhouse
experiments conducted up to the pres
ent time does not support this view,
but conclusive evidence is dependent
on IurIner investigation.
AS far as Is known at the present
time 1t is safe to take seed from a
rusted field. 1t is necessary, however,
that the lightweight, shrunken ker,
nels be removed and only the heaviest
seed obtainable used from such a
field. Much of the wheat from this
years crop is of very poor quality,
and should be thoroughly famed and
screened. Special effort should be
made this year to provide for good
seed wheat for next year. Germina-
ton tests, of course, should be made.
Cooperative Work.
A number of state experiment sta
tons are vitality interested in the rust
work and are cooperating with the
cereal pathologist of the department.
The stripe rust in the western states,
its distribution and occurrence, togeth-
er with its life history and varietal re-
lations, are at present under investi-
cation.
There is also considerable co-opera-
tive work being done on the variety
testing and breeding of cereals for rust
resistance. The major portion of this
work is devoted to wheat, but oats is
also receiving some attention. In this
work rust nurseries are maintained at
four experiment stations where each
year an artificial epidemic is secured,
thus allowing for continuous rust rec
ords on any given variety, and also in
surfing the most severe rust conditions
possible. Work on spring wheat is in
progress at the Minnesota station; at
the Iowa station on spring oats; at the
Kansas station on soft winter wheats !;
and at the Tennessee station on soft
winter wheats and winter oats. The
field trials on rust resistance are sup
plemented by greenhouse tests, where
both Seeding and mature plants are
artificially inoculated with rust and
degree of infection noted.
Testing and Breeding.
The results on the variety testing
for resistance up to the present time
have demonstrated several general
facts. None of the common, or So
called bread spring wheats, is to any
useful degree immune to the stem
rust attack. The most commonly
grown of these susceptible varieties
of spring wheats are the Flies, Blue
stems, and bearded wheats, including
such varieties as Marquis, Power Fife,
Haynes Bluestem, Prelude and Pres
ton. On the other hand, it has been
abundantly demonstrated that certain
varieties of durum and emmer are ex-
tremely resistant to the rust in con-
trast to the common spring wheats.
This fact has been very clearly dem
onstrated in the rust epidemic of the
past season, where the common
wheats, as well as many varieties of
durum wheats were very heavily rust
ed, while other adjacent rows of du-
rum wheat were practically clean of
rust. In the field many farmers suf-
fered severe loss in their durum crop
on account of the rust, while others
obtained yields of two to three times
as many bushels of better grade wheat
than was obtained from the common
bread wheats in the same vicinity.
This demonstrates very strongly the
necessity for planting, where durum
wheat is successfully grown, only the
resistant types.
Fertilizers and Rusts.
The results, obtained particularly at
the Minnesota station in determining
the effect of artificial fertilizers on
rusts indicate that soil fertilizers do
not play an important part either for
or against resistance in a real field
epidemic, and that as factor in farm
practice, the relations between the APP
plication of commercial fertilizers and
the rust can largely be disregarded.
1t seems highly improbable that any
control of rust through the applica-
ton of any reasonable amount of COM
mercial fertilizers can ever be hoped
for.
Control Measures.
e t. - L