The western sentinel., 1895-10-31
Rust In Small Grain.

The rust disease OF wheat OATS bar
ley and grasses generally, are caused
by one or more of three species of mi
croscOpic fungi. The most COMMON
rust on grasses in this State is Pucinnio
grdminis, generally called ''Mildew"
on grasses, and BLACK Rust on
cereals. Our most common rust fun
gus on small grain is Pucinnia RubiqO-
rera, usually called Red Rust" Pu-
cinniG corOndtd, also called Red rust is
the third. The last species is more
common on oats than on any other
and might be properly called oat rust
All three species belong to the class of
parasite fungi called HeterGcismdl, that
is to say. fungi which at different
times in the cycle of their growth live as
parasites upon two or more hosts.
Grass nlildew, Pucinnia grGminis,
begins its spring growth by at
tacking the young leaves of the Bar
berry. Mahonia, and possibly other
shrubs. Upon these it produces small
redish patches with elevated margins
called ''cluster cups" These cups are
filed with the red Aecidio spores of
the fungus which waited by the air or
carried by insects. birds or other agent
fall upon the leaves of grasses or cereal
grains and there penetrate the
leaves through the breathing spores.
Once within the leaf the spore sends
forth a net work of root-like tissue called
Mycelum- Through this. it sucks up the
sap that should go to nourish the seeds
of the plant and these latter shrivel
up. Very soon the fungus bursts
through the epidermis of the leaf and
appears upon the outside as the we'll
known, elongated, narrow red spots.
popularly called Red rust These
are the uredo spores of the fungus and
are able to reproduce themselves upon
L..
and subsequently they produce the
last form in the life cycle, the black,
teleuto spores which form the narrow
black lines seen on the leaves and
stems of cereals and grasses in late
summer and fall These black spores
are the winter or resting spores and
will under favorable circumstances re-
tain their vitality in the straw or even
on the ground for a year or more.
Eventually some Of them alight upon
the leaves of their alternate host and
there produce again the cluster cups
and Aecidio spores and these the uredo
and teleuto spores.
The three fungi which attack grasses
and cereals do not all have the same
alternate host Pucinnia granainis
has for alternate hosts, the barberry,
mahonia and probably other shrubs.
PuciT7aid corOndtd, has for its alternate
hosts the buck thorns, Rhanaus ldnceO-
lota, frangula and other species. Puci1a-
| ez1 Rubigo-perd has for its alternate
hosts the common and disagreeable
weeds Viper's buglass, EcItiun, UttIqare
and Cromwell, Lithospermuna arUense
Knowing that to complete their cycle
Of growth these fungi require host
widely different from grasses and
| grains Ii we could extirpate all such
| host plants within a half mile or so of o
| grain OF grass Ield we could effectually
stop their further development. Yet
we can not hope to exterminate these
/ pests In one or two seasons even by
/ completely destroying their alternate
host-plant. Once the "Red rust" or
uredo spores of the Coronota and Rub
Sg0-VerG species are produced on grains
| or cereals, these in our warm climate
where growing giumaceous plants are
found in green condition all the year
round may go on reproducing
themselves indefinitely as well as pro-
ducing at the same time the succeeding
black form, the teleuto spores, which
are then able to stock the ground or in
feet any chance alternate host plant
which negligence or accident may al.
low to remain.
As these spores are extremely small
and light and are produced in almost
incredible numbers the few alternate
most plants which may survive even
the most watchful care may supply
Bcidio spores enough TO infect hundreds
OF acres OF grass or grain.
Common and destructive as the rust
fungi are in the United States, in Aus
tralia they are still more so and several
conventions of scientific men aud prac-
tical farmers have been held there to
devise methods for repressing the pests
but so far without much success
Practical experience recommends the
following measures:
1. Use dry or well drained land for
small grains
early matnrinE varieties Of wheat.