Barbour County index., 1884-01-25
Wheat Rust.

To begin at the beginning: rust.
whether on wheat. oats. barley or any
other cereal. Is u parasitic plant of vcry-
simple structure. hut rather complex
habits. When we u,e the term plant
in this connection i mus; be understood
n having the same meaning rs when it
j applied to ordinary vegetation.
Wheat rust j, - much plant ~ an
oak tree j.. The two stand well toward
opposite extremes of the vegetable
kingdom, the first being small and
simple in makeup, while the latter is
large and wonder.ully complex. More
over, while the OAK tree is possessed of
green leaves which can gather food
from the air. and roots which draw
nOuriShment from the water and the
earth. the rust plant has none of these.
Think of microscopic oak tree with
neither leaves nor roots; now that is the
condition of the rust-plant.
How then can such plant get the
food wherewith To grow? 1t does Just
what we might expect il to do. 1t
steals its food from plants which have
leaves and roots. 1t Is a thief, or rs we
say in botany. il is parasite. Simple
rs a rust-plant :, its round life is quite
complex. Its first stage is passed on
the harlerry leaf. whcr, il may be found
IN the spring forming yellow patches.
Under n common hand-lcns these
IatcseS are seen to Ice made of many
beautiful little cups. hence the common
name of this stage i ''cluster-cups. "
Each cup is filed with orange-colored
spores. TheRatter soon fall ont and
are blown by the winds. some finally
alighting upon the leaves of wheat:
here they germinatc, and soon penetrate
the skin o. the leaf. an! begin a process
of rapid growth in the soft interior it's
sues. In q few d1ys if the conditions
have been favorable. masses of reddish
srores are formed by the. parasite uSt
beneath the surface of the leaf. and
these finally br, ak through the skin.
forming now the rcd-rust patches 50
common OH grain. Every rcd-rust
sporc may produce more rcd-rust. di-
rrcily. by falling upon leaf and ger
minating thcrc. In this manner sma' !
amount Of rust in field may. under IA
vOrablc condition, thigh temperature
with an abundance of mOisture). give
rise to enOngh To destroy The whole
crop.
The red rust spores appear - be i'm.
capable q! living through the winter. SO
there are produce a little later. from
the same parasitic. larger black patches
NJ thick-walled spores. This is the
black rust stage, and i the last TO ap-
pear. IL often natures after the stalk
l. dead. and so appears at first SIGHT g.
be much less harmful than the proceed.
inc fs.sI 4
spores are 50 tough skinned that they
endure the W ntsr, and the next srr.ne
gcrminate in great numbers They
lirst grow little thread Ike stalk, and
un this are produced several excess vely
small spores. known as sporidia. These
last, on account. OF their minuteness. are
widely dispersed by the winds. and
some, falling upon harberry leaves.
germ nate here, and thus start the bar.
berry cluster cup. The compl te round
OF life j. a follows: QD the cluster
cup on the lar. erry, (2) the rel rust
en- the wheat. 60 the black rust on the
wheat, (4) the termination of the black
ru-t spores, forming Sporidia, which in
turn then produce M. ! again. Until
re- emily NO variation from this round of
life was known. hut last year Mr. Plow-
right, an English investigator. made
the important discovery that the sporid-
dia. VIII ch can not affect q leaves. are
abe TO germinatc upon. and enter into,
the very young leaves of the wheat
When they do tnis they produce direct
" the red rust stage, the cluster-cup
stage being omitted.
Now let us consider the significance
ttrhn
ing at the same time that tne sporidia
are produced, the YOU 2 wheat plants
become inOculated with the parasite.
Winter wheat germinates in the fall,
while the sporidia are produced in the
spring; there i here no danger then.
But it is far different with spring wheat,
which terminates at the exact time the
sporidia are forming. Here, then, is the
explanation of the fact that rust is CON-
mon in some regions where the barber
ry is not grown; it is simply that the
cluster-cup stage is omitted. because of
the fact that the sporidia are able To in
oculate the leaves of the Young spring
wheat plant. There is not space for a
further discussion Of this matter now.
but one suggestion may be made, and
that Is that it is very clear that straw
whichhas black rust upon il is not good
thing to have scattered around upon the
farm in early spring. Last spring |
found the black spores producing myr-
lads of sporidia uron straw which had
been used for the winter protection of
strawberries. Such straw j. much more
dangerous than an equal amount OF
Canada thistle stems tilled with their
leeds, Pro- G, +, Besseg.