A Database for Triticeae and Avena
CEREAL DISEASE LABORATORY
(formerly CEREAL RUST LABORATORY)
USDA-ARS, University of Minnesota, 1551 Lindig, St. Paul,
MN 55108, USA.
D.L. Long, J.A. Kolmer, Y. Jin, M.E. Hughes, and L.A. Wanschura.
Wheat stem rust (Puccinia graminis f. sp.
tritici). The first reports of wheat stem rust in 2004
were in late April, when trace levels of infection were found
in plots at Giddings in central Texas and at Quincy in the Florida
panhandle. The next report of wheat stem rust was in early June,
when trace to 5% severities were reported in a wheat breeding
nursery in northeastern Kansas. In early June, traces of wheat
stem rust were found in an experimental line in a nursery in northeastern
In late June, severe stem rust was observed in plots of the
susceptible cultivar Red Chief at Lincoln, NE. In late June, traces
of stem rust were found in a field of triticale in southeastern
Minnesota, which is in the same area where barberry bushes occur.
The stem rust found on triticale was determined to be rye stem
In the first week of July, trace levels of stem rust infections
were found on the susceptible spring wheat Baart in southern Minnesota.
By mid-July, 20-60 % severities were observed on Baart in central
Minnesota and central South Dakota plots. All of the current spring
wheat cultivars are resistant to the current race population.
In susceptible winter wheat plots in east central Minnesota, trace
to 60 % severities were found at the soft dough growth stage.
In mid-July, traces of wheat stem rust were found on winter wheat
in west central Wisconsin. In late July, trace to 20 % severities
were observed on the susceptible spring wheat Baart in central
North Dakota and north central Minnesota.
From April to June, there were very few reports of wheat stem
rust being found in the southern and central plains. However,
in July stem rust was present on susceptible cultivars at many
locations from western Wisconsin to central North Dakota. Therefore,
the stem rust that developed throughout the north must have originated
from the few inoculum sources in the southern and central plains.
Race QFCS, the predominant race found in the Great Plains the
past few years, was again the predominant race identified in 2004
(Table 1). The majority of wheat varieties in the United States
are resistant to race QFCS. Races MCC and TPMK were found at localities
where field inoculation was used in the screening nurseries. Race
QCCN, a race similar to QCCJ in virulence, was identified from
a collection from Washington.
Table 1. Races of Puccinia graminis
f. sp. tritici identified from wheat in 2004. Pgt race
code after Roelfs and Martens (Phytopathology 78:526-533). Race
QFCS virulent to Sr5, Sr8a, Sr9a, Sr9d,
Sr9g, Sr10, Sr17, and Sr21; MCCF virulent
to Sr5, Sr7d, Sr9g, Sr10, Sr17,
and SrTmp; MCCD virulent to Sr5, Sr7d, Sr9g,
Sr10, and Sr17; TPMK virulent to Sr5, Sr7b,
Sr8a, Sr9d, Sr9e, Sr9g, Sr10,
Sr11, Sr17, Sr21, Sr36, and SrTmp;
and QCCN virulent to Sr5, Sr9a, Sr9g, Sr10,
Sr17, and Sr21. Set four consists of Sr9a,
Sr9d, Sr10, and SrTmp.
Wheat leaf rust (Puccinia triticina). Southern Plains.
In late January, traces of leaf rust were found in central
Texas plots. Cool temperatures during early February slowed leaf
rust development. By late February, 40 % leaf rust severities
were observed in central Texas plots. In the second week of March,
60 % leaf rust severities were reported on susceptible cultivars
in southern Texas (east of San Antonio). Leaf rust was scattered
and severe in more places throughout Texas than in 2003.
By early March, leaf rust was present in Oklahoma but at lower
severity levels than in the previous autumn. In 2004, cold temperatures
during mid-January to mid-February were not conducive for over
wintering of rust in Oklahoma.
In late March, in southern and central Texas, leaf rust infections
were at low severity levels in most commercial wheat fields (Figure 1) and at high
severity levels on susceptible cultivars in nursery plots. Leaf
rust severities up to 80 % were found on lower leaves of cultivars
in nurseries, and trace-20 % severity levels were on lower leaves
in fields. Rainfall in mid to late March contributed to the leaf
rust development in the southern Great Plains.
In mid-April, leaf rust was found from Texas to Kansas. In
most of southern and central Texas, rain and dew periods were
ideal for the infection process to occur. In a central Texas nursery
on the susceptible cultivar Jagger, the leaves were completely
dead due to heavy rust infections.
In late April in central Texas, susceptible cultivars had moderate
to high severities of rust infection, whereas in northern Texas,
susceptible cultivars had light to moderate leaf rust infection.
In central Texas fields, 40 % severities were observed in fields
that had been sprayed with fungicide (Figure 1). By early May, leaf rust was increasing
throughout Oklahoma, but drier than normal conditions in mid-May
significantly slowed rust development. As in previous years, Jagger
wheat was heavily rusted and some yield reduction occurred. Leaf
rust in the southern Great Plains was more severe than 2003, but
dry conditions in some areas slowed rust development.
Central Plains. In early April, traces of leaf rust
were found in several fields in south central Kansas. In early
May, leaf rust was present in most of Kansas at trace severities
except in south central Kansas where 10 % severities were reported
on lower leaves in some fields. By the third week in May, leaf
rust was starting to increase on flag leaves in south central
In the last week in May, leaf rust was severe in plots and
fields of susceptible cultivars from north central Kansas to west
central Missouri (Figure
1). At the late berry stage in south central Kansas, Jagger
had 60 % rust severities on flag leaves while in northeast Kansas,
Jagger had 20 % rust severities. In central Kansas varietal plots,
rust severities ranged from trace to 80 %. In southern Kansas,
losses due to leaf rust were severe in Jagger, whereas other leaf
rust susceptible cultivars had lower yield losses (Table 4). Rainfall in late May, in Kansas
and Nebraska allowed leaf rust to increase which provided inoculum
for the northern wheat growing area.
In mid June, leaf rust was severe in southeast and south central
Nebraska (Figure 1).
Rust severities on flag leaves were 60 to 80% in fields and experimental
plots. Abundant rainfall in eastern and southern Nebraska provided
good moisture conditions for rapid increase of leaf rust infections.
In western Nebraska where it was much dryer, only trace levels
of leaf rust infections were observed (Table 4).
Northern Plains. In early June, trace amounts of leaf
rust were found on winter wheat lines in plots at Brookings in
east central South Dakota.
In early June, trace levels of leaf rust were found in winter
wheat plots in east central Minnesota. Traces of leaf rust infections
were also found in spring wheat in the Red River Valley in early
June. In mid-June, leaf rust was increasing in winter wheat in
southeastern South Dakota and southern Minnesota, with severities
of 20-40 % on lower leaves and 10-20 % on flag leaves. The spring
wheat crop had trace to 5 % levels of infections on lower leaves.
In mid-June in an east central South Dakota rust nursery, high
levels of leaf rust were observed on the susceptible spring wheat
cultivars Thatcher, Baart, and Morocco. During the second week
in June, traces of leaf rust were found in fields in southeast
and north central North Dakota. Rainfall and cool-warm temperatures
provided suitable conditions for the increase and spread of leaf
rust in the north central region.
In early July in east central Minnesota plots, susceptible
winter wheat cultivars such as Jagger had 80 % rust severities,
but the resistant cultivars had only trace levels of infections
on the flag leaves. The leaf rust did not over winter in the Minnesota
plots, but probably originated from field infections in Oklahoma
In early July, susceptible spring wheat cultivars in southern
Minnesota plots had 20 % rust severities, with most infections
on the lower leaves. Trace levels of leaf rust were observed in
many of the spring wheat fields in southern Minnesota (Figure 1). In the first week of July, leaf
rust severities were up to 80 % on susceptible spring wheat cultivars
such as Ingot in southern and west central Minnesota varietal
plots. The spring wheat Oxen, which is commonly grown in southern
Minnesota, had leaf rust severities of 30-60 %; the cultivar Alsen
had leaf rust severities of 5-10 % in southern and west central
In mid-July, 10-40 % leaf rust severities were observed on
flag leaves of spring wheat cultivars in fields from northwestern
South Dakota to northeastern Wisconsin.
In late July, spring wheat varietal plots had trace to 60 %
leaf rust severities in central and eastern North Dakota. Fields
in southeastern and central North Dakota of commonly grown wheat
cultivars had severity levels of 20 %. Many wheat fields were
sprayed with fungicide to prevent losses due to rust and scab.
In the northern tier of counties in North Dakota leaf rust was
at reduced levels because the crop maturity was later than normal.
This year leaf rust was severe and concentrated in the upper
Midwest. Rust inoculum arrived from the south in late May and
early June with rain showers while temperature and moisture conditions
were good for infection and spread of leaf rust. The spring wheat
cultivars currently grown have less effective resistance to leaf
rust than those that were popular 10-15 years ago. Losses to wheat
leaf rust occurred in cultivars that had not been sprayed with
fungicide. In 2004, a 10 % loss in the spring wheats to leaf rust
was determined in Minnesota (Table
Southeast. In mid-January, leaf rust was reported in
southwest Louisiana. By early March, leaf rust was at significant
severity levels in south/west central Louisiana. Rust was widespread
and severities of 30 % were in nursery plots and fields. Some
cultivars had heavy rust severities on older leaves (fall infection),
but low severities on the upper leaves.
In mid-February, fields and plots in Baldwin County in southwest
Alabama had low severities of leaf rust. In late February weather
conditions were ideal for further rust development in the southeastern
In late March, leaf rust was present in fields and plots in
the southern soft red winter wheat area from Georgia to Arkansas.
Some of the fields infected with rust were sprayed for rust control.
In mid-April from central Louisiana through Alabama to Georgia,
low levels of leaf rust infection were observed in research plots
and fields. On a few susceptible cultivars 40 % severities were
reported in south central Louisiana nurseries. In early May, plots
from central Texas to the Florida Panhandle had 80 % leaf rust
By mid-April, leaf rust was increasing in areas of Arkansas
that had sufficient moisture. In late April, light to moderate
leaf rust was in Arkansas fields and plots. In early May nursery
plots in northwestern Arkansas had 50 % rust severities. In mid-May,
leaf rust was prevalent throughout Arkansas, but rust infections
developed later than normal and did not cause much yield loss
Mideast. In late May, susceptible cultivars had 20-25
% leaf rust severities at the late milk stage in southwest Indiana
wheat plots. This was the most leaf rust seen in a number of years
in this area. In early June, plots in west central Indiana had
20 % severities while traces were found in fields.
In early June, leaf rust developed late in central Ohio and
susceptible cultivars had 20 % severities on flag leaves, which
resulted in losses. During the second week in June, trace to 10
% severities was found in plots in northwest Ohio, northern Indiana
and south central Wisconsin. Only light losses occurred in this
area (Table 4).
East. In late May, hot, dry weather hastened the maturity
of small grains in the Carolinas and Virginia. Powdery mildew
was widespread on wheat and in some fields appeared to be at damaging
levels. Leaf rust on winter wheat was either nonexistent or very
light in commercial fields. In nursery plots in eastern North
Carolina, leaf rust was severe only on fully susceptible cultivars.
In eastern Virginia, the wheat crop matured 10 days earlier
than normal because of the hot temperatures in May, which halted
the leaf rust development. In early June in western Virginia,
the crop matured at a normal pace and more leaf rust was found
there. Varieties with Lr26, e.g., USG 3209 and Sisson,
had considerable leaf rust. In early June, moderate to light levels
of leaf rust infection were observed in winter wheat plots in
In early July, wheat leaf rust was widespread, but not severe
throughout western and central New York.
California. Wheat leaf rust was late to develop and
was only found on a few cultivars. The wheat crop matured early
and leaf rust did not affect the yield.
Pacific Northwest. In late May, trace amounts of leaf
rust were observed in wheat plots and fields in northwest Washington.
In early June, severe leaf rust was reported in the Willamette
Valley in northwest Oregon.
In late June, foci of 20 % leaf rust severity were found in
soft white winter wheat plots in northeastern Oregon at Pendleton.
Leaf rust development was light in the Pacific Northwest this
Canada. In mid-June, traces levels of leaf rust were
found in winter wheat plots south of Winnipeg, Manitoba, Canada.
Wheat leaf rust virulence. The 2004 leaf rust race identifications
are presented in Table 2 and Table
3 (see Figure 2
for agroecological area map). A total of 50 leaf rust races were
found in the U.S. From the central and southern Plains the most
common races were M- (virulent to Lr1, Lr3, Lr10,
and Lr17) (Table
3). Many of the MBDS and MCDS races were identified from collections
made from Jagger, which is widely grown in the southern and central
Plains states. The number of T-races (TNRJ and TNBJ) with virulence
to Lr9, Lr10, and Lr24 in collections made
from the cultivars Lockett (Lr9 resistance ) and Thunderbolt
(Lr41 resistance) has increased. In 2004, the most common
races identified in the northern wheat growing area were T-races
(TBBJ, TBDS, and TCDS). At the same time, there was an increase
in the number of K-races (virulent to Lr2a, Lr2c,
and Lr3 (Table
2). In the soft red wheat area the most common race was MCRK
(virulent to Lr1, Lr3, Lr3ka, Lr10,
Lr11, Lr14a, Lr18, Lr26, and Lr30).
Some of the commonly grown cultivars in this area have Lr11
and Lr26 resistance.
Wheat stripe rust (Puccinia striiformis f. sp. tritici).
Southern Plains. In late February, severe wheat stripe rust
was found in plots southwest of Houston, Texas. By the second
week in March, the stripe rust development in these plots had
stopped. In mid-March, there were reports of stripe rust in fields
west of Brazos and Williamson counties in central Texas.
In late March, wheat stripe rust infections were at low levels
in fields in southern and central Texas (Figure 3). Stripe rust severities ranged from
trace levels to 20 % in plots and fields. Although rainfall in
late March provided high moisture conditions, warmer day and night
temperatures restricted stripe rust development. In mid-April,
stripe rust was light in southern and central Texas.
In late April, stripe rust was light to moderate in north central
Texas and southern Oklahoma plots and fields (Figure 3). In north central Texas, 60 % severities
were observed on susceptible varieties. Some fields in this area
had been sprayed for rust and mildew control. In early May, stripe
rust was found across northern Oklahoma. Rust was present in significant
amounts, but dry and windy conditions impeded the further development
of stripe rust on susceptible cultivars. Hot spots of rust development
were found in central and southwestern Oklahoma, but not at levels
that caused significant yield losses (Table 4).
This year stripe rust was found in fewer locations and the
weather conditions were not as conducive for stripe rust development
as 2003 in Texas and Oklahoma. Another possibility is that stripe
rust over wintering was reduced compared to previous years. Stripe
rust infections in the southern U.S. were less severe and extensive
than 2003 and provided less inoculum for the northern wheat growing
Central Plains. In mid-May, stripe rust was at trace
levels on flag leaves in a central Kansas field. In late May,
stripe rust was at trace-10 % severity on flag leaves in southeast
and south central Kansas fields. Stripe rust was much lighter
than last year in this area. In 2003 there was 10.6 % loss to
stripe rust in Kansas, whereas in 2004, there was 0.1 % loss (http://www.cdl.umn.edu/loss/loss.html).
In late May, low levels of wheat stripe rust were found on
flag leaves in north central Kansas (Figure 3). The warm and dry conditions in
May reduced further development of stripe rust in Kansas.
In mid-June, stripe rust was not observed in fields or plots
in Nebraska, possibly due to the heavy leaf rust infections.
Northern Plains. In early June, stripe rust was found
in winter wheat plots in east central South Dakota.
In mid-June, trace levels of stripe rust were in winter wheat
fields in south central South Dakota, and in fields of spring
and winter wheat in eastern South Dakota (Figure 3). In winter wheat plots at Brookings,
most lines had trace levels of stripe rust infection, however
a few plots had very high levels of infection on flag and lower
leaves. By the third week in June, trace levels of stripe rust
were on spring wheat in St. Paul, Minnesota plots.
In 2003, in early June, traces of stripe rust were found in
winter wheat plots in east central Minnesota, but in 2004 stripe
rust infections were not found until mid-June at this location.
In early July, stripe rust severity levels of 60 % were present
in west central Minnesota spring wheat fields and plots (Figure 3). The cultivars Trooper and Walworth
were the most susceptible with stripe rust infections over 50
%. Most of the commonly grown spring wheats have moderate to high
resistance to stripe rust. The very cool temperatures with sufficient
moisture levels were conducive for stripe rust development in
the north central region.
In mid-July, hot temperatures arrested development of stripe
rust on spring wheat in the northern Great Plains. In late July,
a spring wheat field in north central Minnesota had 5 % severity
where night time temperatures had been more conducive for rust
Louisiana, Arkansas, and Missouri. In late February,
low levels of stripe rust infections were in southern and east
central Louisiana fields. By early April, rust had increased and
these fields were sprayed for rust control. By mid-April in northeast
Louisiana, stripe rust was severe in soft red winter wheat varietal
plots. Some fields were sprayed to reduce losses due to rust.
Significant amounts of stripe rust have occurred in five of the
last seven years in Louisiana.
In late March, wheat stripe rust was found in fields throughout
southeast Arkansas and fungicide application was recommended.
In mid-April in southwest Arkansas wheat plots, little stripe
rust was found on the most commonly grown varieties. In late April,
stripe rust was at trace levels in eastern and northern Arkansas.
By early May, in northern Arkansas, some cultivars had 100 % stripe
rust severities. In mid-May, stripe rust development had ceased
in Arkansas because the high temperatures at night were not conducive
for stripe rust increase.
In late May, 5-10 % stripe rust severities were observed in
soft red winter wheat fields in west central Missouri. Stripe
rust severity was less than last year in this area and the crop
was 7-10 days earlier than normal. Traces of stripe rust were
observed in plots and fields in northeastern Missouri in early
Mideast. In early May, stripe rust was light in wheat
fields in southwestern Illinois. Traces of stripe rust were in
west central Indiana plots in early June During the second week
in June, stripe rust foci of 10 % severity were located in winter
wheat plots and fields in northern Indiana and south central Wisconsin.
During the second week in June, traces of stripe rust were
found in plots in central, northeast and northwest Ohio.
In early July, 20 % severities were observed in fields of soft
red winter wheat in northeastern Wisconsin.
California. Stripe rust on wheat was first detected
on 12 February in the UC Regional Wheat Nursery in the Sacramento/San
Joaquin Delta nursery in California. Rust was scattered throughout
the nursery in light amounts (less than 1 % incidence), but pustules
on infected plants were sporulating profusely. Infected leaves
had up to 30 % severity. By early March, wheat stripe rust had
increased to 50 % severity and 20 % incidence in the nursery at
Sacramento/San Joaquin Delta. The crop was in late jointing stage.
In early March, low levels of wheat stripe rust were found in
nurseries in Madera county and Davis, California.
In Mexico, wheat stripe rust in the southern Sonora state was
not as severe as in previous years. However, northern Sonora and
the neighboring state of Baja California had more rainfall. This
area (Mexicali Valley) is close to a U.S. wheat growing area where
stripe rust could have an economic impact.
In mid-April, wheat stripe rust was severe in susceptible varieties
in nurseries in the Central Valley and Sacramento Valley of California.
In the same area stripe rust was at low to moderate severities
on durum varieties. Stripe rust infection foci were observed in
fields in the Sacramento Valley.
In mid-July, spring wheat plots had 40 % stripe rust severities
spring wheat plots at the early dough growth stage in northeastern
California at Tulelake. Stripe rust foci also were detected in
plots of wheat at 90 % severity, and 30 % incidence in a north
central California nursery.
In California, yield losses from stripe rust were considerably
less than in 2003 because of the wide-use of resistant varieties
and the late development of heavy rust infections (Table 4). One concern in 2004 was that new
rust races have developed that are virulent to the resistance
that was effective in 2003 and much of the 2004 season. These
races may survive in the stripe rust population and appear in
higher frequency next season.
Pacific Northwest. In early March, severity levels of
30 % were in winter wheat fields and plots in northwestern Washington.
Stripe rust was uniformly distributed in commercial fields. Stripe
rust severity and distribution patterns were typical for this
area. In late March stripe rust was not found on the eastern side
of the Rocky Mountains in Washington.
During the last week of April, stripe rust was starting to
increase in experimental plots in northeast Oregon and southeast
Washington. Near Connell, Washington, severity levels of 20 %
were in fields planted with the HRWW Hatton. In 2004, the appearance
of stripe rust was much later than 2003, because of the dry weather
in the autumn of 2003 that reduced fall infection and a cold winter
that reduced winter survival. The stripe rust infections were
on the top leaves, indicating infections occurred mostly after
the winter season. The rust infected winter wheat produced rust
spores that infected spring wheat crops in central and eastern
Washington and northern Idaho.
By late May, wheat stripe rust was observed on susceptible
spring and winter wheat cultivars growing in fields and plots
in central and eastern Washington and northern Idaho.
In late June, wheat stripe rust was developing very rapidly
in fields of susceptible winter and spring wheat cultivars in
eastern Washington. Many of these cultivars have high temperature
adult plant resistance, which reduced rust losses. Some fields
had incidence levels of 60 % stripe rust and severity levels of
20%. Fungicides were applied on susceptible wheat fields. Plots
of susceptible lines had 80 % severities near Pullman, Washington.
In 2004, yield losses to stripe rust occurred in the Pacific Northwest,
but were less than 2003 (http://www.cdl.umn.edu/loss/loss.html).