Biology Reference
In-Depth Information
Puccinia calcitrapae var. centaureae (for-
merly
Puccinia carthami
). Widely distributed
on safflower in Great Plains and California.
Spores carried on seed or persisting in soil infect
seedlings, which often die.
Puccinia canaliculata
Rust
on purple nutsedge
and yellow nutsedge.
Puccinia
in north central and northeastern states; II, III on
wheat and other cereals and wild and cultivated
grasses.
This is the classic example of rust, the one
used in school textbooks and known through the
ages as the major limiting factor of wheat pro-
duction. Proof of the connection between bar-
berry and wheat in the life cycle was not made
until 1864, but long before that farmers
had noticed that wheat suffered when barberry
plants were near. France in 1660, Connecticut in
1726, and Massachusetts in 1755 enacted
laws requiring the destruction of barberry near
grain fields.
There are six commonly recognized varieties
of stem rust:
Puccinia graminis
f. sp.
avenae
-on
oats, sweet vernal grass, brome grasses, some
fescues.
P. graminis
f. sp.
agrostidis
-on redtop and
other
Agrostis
spp.
P. graminis
f. sp.
graminicola
—on St. Augus-
tine grass.
P. graminis
f. sp.
phlei-pratensis
-on timothy
and some related grasses.
P. graminis
f. sp.
poae
-on Kentucky and other
bluegrasses.
P. graminis
f. sp.
secalis
-on rye, some wheat,
and barley grasses.
P. graminis
f. sp.
tritici
, wheat rust - on wheat,
barley, rye, and many grasses.
Stem rust occurs wherever wheat is grown, but
is most serious in northern states. It is dependent
on weather conditions, with epidemics and disas-
trous losses in certain seasons. The amount
depends on the maturity of the crop when rust
strikes, but losses may run 25 % of expected yield
for the nation and much higher for individual
states. There are a great many physiological
races.
On grains and grasses the first rust appears as
long, narrow streaks on stems, leaf sheaths, leaf
bases, and distal portions of blades. These streaks
are uredial sori, the epidermis being torn back to
form a white collar around a dark red powdery
mass of one-celled urediospores. Later the same
sori turn black as dark, two-celled teliospores
replace summer urediospores. Stems may be bro-
ken at this stage.
carduorum
Rust
on
Carduss
tenniflorus
and
Carduss thoermeri
.
Puccinia caricina (
P. caricis
var.
grossulariata,
P. pringsheimia
). 0, I on currant, flowering cur-
rant, gooseberry; II, III on
Carex
spp. Common
only on wild species or in neglected gardens.
Leaves are thickened, sometimes curled in red-
dish cluster cup areas; there are enlargements on
stems and petioles, red spots on berries. Control
by eliminating the sedge host.
Puccinia carthami (see
Puccinia calcitrapae
var.
centaureae
). Widely distributed on safflower
in Great Plains and California.
Puccinia
▶
claytoniicola On
claytonia,
Wyoming.
Puccinia conoclinii On ageratum, Ohio.
Puccinia coronata
Crown Rust
of oats; Orange
Leaf Rust of Oats. 0, I on buckthorn and rattan
vine; II, III on oats and grasses. There are several
varieties and many physiological races of this
rust, which is as destructive to oats as leaf rust
is to wheat. Redtop, meadow fescue, ryegrass,
and bluegrass are among the lawn grasses that
may show orange or black pustules on leaves.
Puccinia crandallii 0, I on snowberry, wolf-
berry, coralberry; II, III on grasses, fescues,
bluegrass.
Puccinia cynodontis On Bermuda grass, New
Mexico.
Puccinia cypripedii On orchids.
Puccinia dioicae (
P. extensicola
) in many vari-
eties. 0, I on aster, goldenrod, erigeron, senecio,
lettuce, oenothera, rudbeckia, and helenium; II,
III on
Carex
spp.
Puccinia dracunculi (see
Puccinia tanaceti
var.
dracunculina
). On artemisia, Wisconsin to
the Pacific Coast.
Puccinia flaveriae (see
▶
Puccinia melampodii
).
▶
On
Calendula
.
Puccinia graminis
Stem Rust
of grains and
grasses. 0, I on barberry and mahonia, especially
