Agriculture Reference
In-Depth Information
fi rst was from 1958 to 1961, and the epidemics
were concentrated in the Pacifi c Northwest and
California. Severe epidemics of wheat stripe rust
occurred in 1960 and 1961 in Washington
(Hendrix 1994) and in 1961 in Oregon (Shaner
and Powelson 1971). Stripe rust also was severe
in Idaho and Montana (Pope et al., 1963) in those
years. In California, the yield losses were esti-
mated at 28%-56% in the Sutter Basin north of
Sacramento (Tollenaar and Houston 1966).
The second period of stripe rust epidemics
occurred from 1974 to 1978. In 1974, California
had an 8% yield loss in wheat production. In
1976, yield losses were 17% in Washington, 13%
in Oregon, and 11% in Idaho. The third wave of
epidemics occurred from 1980 to 1984. In 1980
and 1981, stripe rust epidemics were widespread
in the Pacifi c Northwest, and yield losses in
Washington were estimated to be 13% in 1980
and 11% in 1981. Oregon and Idaho had 5%-9%
yield losses during the same period. Yield losses
were reduced in 1980-1981 because of the wide-
spread use of fungicides. From the mid-1980s to
the late 1990s, yield losses caused by stripe rust
were reduced due to widely grown resistant cul-
tivars in the Pacifi c Northwest and California and
the use of fungicides. Yield losses remained below
5% in the western US.
The most recent stripe rust epidemics occurred
from 1999 to 2005. In 1999, stripe rust caused a
7% yield loss in California but was not severe in
other states. In 2000, stripe rust was widespread
and caused severe damage in the south central
states with a 7% loss in Arkansas. In 2001 losses
in Kansas and Colorado were estimated to be 7%
and 8%, respectively. In 2003 states with major
yield losses were Kansas (11%), Nebraska (10%),
and California (21%). In 2005 stripe rust was very
widespread and occurred in more than 30 states,
with signifi cant yield losses in Kansas (8%),
Texas (15%), Oklahoma (5%), Nebraska (4%),
California (5%), Arkansas (5%), and Louisiana
(5%).
mycete rust fungus. The disease was fi rst described
by Gadd in 1777 (Eriksson and Henning 1896).
Schmidt (1827) named the stripe rust fungus as
Uredo glumarum
. Westendorp (1854) used
P. stri-
aeformis
for stripe rust collected from rye. Fuckel
(1860) described stripe rust as
P. straminis
.
Puccinia glumerum
, as described by Eriksson and
Henning (1894), was used as the name for the
stripe rust fungus until Hylander et al. (1953)
revived the name
P. striiformis
Westend.
Since stripe rust pathogens on different cereal
crops and grasses are separated into different
formae speciales
(Eriksson 1894),
P. striiformis
Westend. f. sp.
tritici
Eriks. is considered the
valid name for the stripe rust pathogen infecting
wheat. In addition to wheat stripe rust, Eriksson
described stripe rusts on barley as f. sp.
hordei
, on
rye as f. sp.
secalis
, on
Elymus
spp. as f. sp.
elymi
,
and on
Agropyron
spp. as f. sp.
agropyron
. Later,
three more
formae speciales
were proposed:
P.
striiformis
f. sp.
poae
on Kentucky bluegrass
(
Poa pratensis
L.) (Britton and Cummins 1956;
Tollenaar 1967), f. sp.
dactylidis
on orchardgrass
(
Dactylis glomerata
L.) (Manners 1960; Tollenaar
1967), and f. sp.
leymi
on
Leymus secalinus
(Georgi)
Tzvel (Niu et al., 1991). More recently, Wellings
et al. (2004) considered stripe rust on
Hordeum
spp. in Australia to be a new
formae specialis
, dif-
ferent from both
P. striiformis
f. sp.
tritici
and
P.
striiformis
f. sp.
hordei
. Not all these
formae specia-
les
are equally and clearly separated by host
specialization. Wheat stripe rust mostly infects
wheat but can infect some barley cultivars, while
barley stripe rust can infect some wheat cultivars.
However, stripe rust of barley does not infect
bluegrass, and bluegrass stripe rust does not infect
wheat or barley (Chen et al., 1995).
Puccinia striiformis
has a hemicyclic life cycle of
urediniospores, teliospores, and basidiospores.
Teliospores are formed along the sides of uredinia
and are the same size and shape as urediniospores,
but have black cell walls. Teliospores form more
rapidly and more abundantly under hot and
humid conditions than under cool and dry condi-
tions. The barley stripe rust fungus (
P. striiformis
f. sp.
hordei
) is more likely to produce telia than
P. striiformis
f. sp.
tritici
. Mature teliospores are
two-celled and become diploid with one nucleus
Taxonomy, life cycle, and host range
Stripe rust on cereal crops and grasses is caused by
different
formae speciales
of
P. striiformis
, a basidio-
