Barley Stripe Rust Control in the Klamath Basin
Randy Dove1 1 , Steve Orloff2 , Greg Chilcote l , Don Kirby 2
Introduction
Barley stripe rust (BSR) is a newly
introduced barley pest in the Klamath Basin.
BSR was introduced from Europe into South
America in 1975. By 1990, the disease was
established in central Mexico, and in 1991
incidence of the disease was reported in Texas.
BSR spread to Colorado in 1992, and Arizona
and Idaho in 1993. Several barley plants with
symptoms typical of the disease were found in
the Lower Lake leases in 1994, but laboratory
confirmation of the presence of the disease was
not possible. Economically significant
occurrences of the disease were seen in the
Klamath Basin for the first time in 1995.
The impact of BSR on barley yield can be
devastating, with up to 85 percent yield
reduction reported from Bolivia and Mexico. In
general, yield reduction in the United States has
been less than in Latin America. However, the
cool moist spring conditions of the Pacific
Northwest could provide an ideal environment
for BSR and appropriate disease control
precautions should be taken.
Few winter varieties and no commercially
available spring barley varieties are resistant to
this pathogen. Breeding programs at OSU, UC
Davis, WSU, and USDA research centers in
Idaho are all working to develop resistant
spring and winter varieties. However, seed of
B SR resistant varieties will not be available in
significant quantities for several years. Until
resistant varieties are available, producers must
2
rely on chemical control of the disease.
Chemical fungicides may be applied either
as a seed treatment or as a post-emergence
foliar spray. Baytan is a fungicidal seed
treatment that is effective in controlling early
season infestation by BSR. Baytan has
provided protection against BSR infestation for
5 to 9 weeks after emergence. In areas where
early infestation occurs, Baytan has been
effective in reducing BSR infestation and
increasing yields. Baytan has been included in
several trials in the Klamath Basin to test its
effectiveness against other pathogens for the
last four years. In the absence of BSR, yields
using Baytan have not been different from
standard seed treatments.
Tilt is currently the only fungicide
registered for foliar application to control BSR
on barley in Oregon. Tilt cannot be applied
after flag leaf emergence. Folicur is a systemic
fungicide that should soon be registered in
Oregon for BSR control in barley. A section 18
emergency exemption was available in Oregon
for Folicur in 1996. Folicur may be applied as
late as 50 percent head emergence. Alto is
another new fungicide that should be available
for BSR control in the near future.
Baytan has the same chemistry as Folicur.
The use of both a fungicide seed treatment and
a foliar spray may have interactive effects. The
relative effectiveness of Baytan seed treatment
and foliar fungicides in various combinations
was examined in three locations in the Klamath
Basin in 1996.
Associate Professor, and Research Technician, respectively, Klamath Experiment Station,
Klamath Falls, OR.
Farm Advisor, Siskiyou Co. and Acting Superintendent/Research Associate, Intermountain
Research and Extension Center, respectively, University of California, Tulelake, CA.
Acknowledgments: Henzel Farms provided the Klamath County organic soil site and crop care. The
Experiment Station greatly appreciates their support and participation.
Klamath Experiment Station
109
Procedures
The effectiveness of three foliar
fungicides, either with or without Baytan seed
treatment, was evaluated at a mineral soil site
(KES), an organic soil site on Lower Klamath
Lake, Klamath Co., Oregon (LKL), and an
irrigated organic soil site in Siskiyou Co.,
California (IREC). Colter spring barley was
treated with either a standard seed treatment
(Vitavax RTU) or with Baytan, then with Tilt,
Folicur, or Alto. Two rates of Tilt, Folicur, and
Alto were included at all sites, and a third rate
of Alto at the Oregon sites. An experimental
BSR resistant selection from Idaho
(78Ab10274), was included in the Oregon trials
to evaluate its resistance to B SR under Oregon
conditions. Table 1 details treatment
combinations included in the trials. Foliar
fungicides were applied to plots at
approximately 50 percent head emergence.
Applications were made on July 3 and 12 at
KES and LKL, respectively. BSR infestation at
the time of fungicide application was less than
5 percent.
Plots measured 15 x 40 feet with a row
spacing of 6 inches. BSR infestation was
recorded for all plots at KES and IREC. The
trial at the KES was on land planted in potatoes
the previous year. Soils at the station include
Poe, Fordney, and Hosley series, all of which
have a fine-loamy to sandy texture, and are
moderately deep and somewhat poorly drained.
The LKL site was on very deep, poorly drained,
lake bottom soils with high organic matter
content. These fields are continuously cropped
in spring cereals. All sites were sprinkler
irrigated.
All trials were arranged in a randomized
complete block design with four replications.
The trials at KES and LKL were planted on
May 5 and 10, respectively. Seed was planted
one inch deep at a seeding rate of 100 lb/acre.
All plots received 50 lb N, 30 lb P 2 O5, and 22
lb S/acre by broadcast application prior to
planting, and 30 lb N, 18 lb P2O5, and 13 lb
S/acre banded at planting.
110
At KES, bromoxynil and MCPA were
applied at labeled rates to control broadleaf
weeds. Weed control at organic soil sites was
achieved with a mixture of 2,4-D and Banvel.
Plots were harvested in late September using a
plot combine with a 5-foot wide header. Grain
yield was recorded for all plots. Test weight,
percent plumps, and percent thins were
measured in all replications.
Results
Foliar fungicide application
significantly reduced BSR infestation at KES
and IREC (Tables 2, 3, and 5). Both locations
had similar trends and a two-site average will
be used to discuss BSR infestation below. In
plots not treated with a foliar fungicide, BSR
infestation of Baytan treated plots was
significantly lower than Vitavax treated plots in
Colter at KES (Table 3), but not at IREC (Table
1). There was no significant difference in BSR
infestation between the two seed treatments
when foliar fungicides were applied. Both
Folicur and Alto applications reduced BSR
infestation levels compared to Tilt. The high
rate of Tilt resulted in less BSR infestation than
the low rate at both locations. In contrast, the
higher rates of Folicur did not reduce levels of
infestation at either site. There was no
difference in BSR infestation at KES due to
different rates of Alto application. It appears
that an application of 10 gm ai/acre of Alto in
combination with Baytan seed treatment will
adequately control BSR in the Klamath Basin
(Table 3).
The experimental selection,
78Ab10274, did not have any rust pustules
while untreated Colter had 56 percent
infestation at KES (Table 4). The resistant line
displayed poor agronomic characteristics
similar to its parent, Klages. It yielded only
3,880 lb/acre, compared to 5,870 for untreated
Colter. The development of higher yielding
resistant lines is clearly needed. However, it is
clear that good sources of resistance such as
78Ab 10274 are available.
Klamath Experiment Station
Grain yield did not correlate well with
BSR control in all locations. Grain yield and
BSR infestation were highly correlated at IREC
(Table 2). Plots receiving no foliar fungicide
produced 6,570 lb/acre compared to average
yields of 7,900, 8,060, and 8,110 for Tilt,
Folicur, and Alto treated plots, respectively.
Yield differences between foliar fungicide
treatments were not significant. In general,
there was no difference in grain yield due to
seed treatment.
In contrast, there was no difference in
yield due to either seed treatment or foliar
fungicide application at KES. At LKL, only two
treatment combinations produced significantly
higher yields than the untreated plots, the four
and eight ounce rates of Folicur in combination
with Vitavax seed treatment (Table 4).
Lodging reduction due to foliar
fungicide application was noted at LKL pri - to
harvest. Reduction in lodging included in T:
4 represents lodging compared to adjacent
untreated plots.
Grain quality was positively affected by
foliar fungicide application at all sites. Test
weight increased from an average of 48.2 lb/bu
without foliar fungicide to 49.4, when averaged
across all foliar fungicide treatments (Table 5).
Plumps increased from 73 percent to over 82
percent due to fungicide application (Table 5).
Application of foliar fungicide was
economically beneficial at only one site, IREC.
An increase in average yield of 1,500 lb/acre
due to foliar fungicide application would result
in an additional $75/acre in net sales with a
grain price of $100/ton. Fungicide and
appplication costs vary, but should not exceed
$35/acre.
Table 1. 1996 Foliar Fungicide Trial Treatments. Seed and foliar fungicide treatments and
varieties were not identical at all locations in 1996. Additional entries were included at
Klamath Experiment Station (KES) and the Lower Klamath Lake location (LKL) and
are detailed below.
Location
Treatment
IREC
LKL
KES
Foliar
Seed
Variety
None
Vitavax
Colter
None
Baytan/Captan
Colter
Tilt 4 oz
Vitavax
Colter
Tilt 4 oz
Baytan/Captan
Colter
Tilt 8 oz
Vitavax
Colter
Folicur 4 oz
Vitavax
Colter
Baytan/Captan Folicur 4 oz
Colter
Folicur 8 oz
Vitavax
Colter
Baytan/Captan. Alto 10 gm
Colter
Alto 20 gm
Vitavax
Colter
Baytan/Captan Alto 20 gm
Colter
Alto 40 gm
Vitavax
Colter
None
Vitavax
78Ab10274
Tilt 4 oz
Vitavax
78Ab10274
Klamath Experiment Station
X
X
X
X
X
X
X
X
X
X
111
Table 2. Foliar Trial at IREC. Seed treatment and foliar fungicide effects on barley stripe rust
infestation (BSR), grain yield, test weight, and thins of Colter spring barley planted at the
Intermountain Research and Experiment Center (IREC), Tulelake, CA in 1996.
Treatment
Seed
Entry
Foliar
BSR
Thins
5.5/64
6/64
lb/A
ib/bu
44.0
45.0
54.9
60.1
34.4
28.5
1
2
Vitavax
Baytan/Captan
None
None
40
6650
6490
3
4
5
Vitavax
Baytan/Captan
Vitavax
Tilt 4 oz
Tilt 4 oz
Tilt 8 oz
16
8
4
8190
7610
7890
46.0
47.0
48.0
74.3
73.1
80.4
19.2
19.5
14.4
6
7
8
Vitavax
Baytan/Captan
Vitavax
Folicur 4 oz
Folicur 4 oz
Folicur 8 oz
1
2
0
8090
8020
8010
47.0
47.0
47.0
83.1
81.2
85.7
12.0
14.0
10.6
9
10
Vitavax
Baytan/Captan
Alto 20 gm
Alto 20 gm
0
0
8170
8040
48.0
45.0
80.1
75.0
15.4
17.0
Mean
12
7720
46.0
74.8
18.5
LSD (0.05)
10
330
2.0
6.6
4.4
CV (%)
60
3
2
6
17
112
44
Yield
Test
wt
Klamath Experiment Station
Table 3. Foliar Trial at KES. Seed treatment and foliar fungicide effects on barley stripe rust
infestation (BSR), grain yield, test weight, and thins of Colter and 78Ab 10274 spring barley
planted at the Klamath Experiment Station (KES), Klamath Falls, OR in 1996.
Variety
Seed
Thins
Test
Treatment
Foliar
BSR
Yield
wt
6/64
%
lb/A
lb/bu
Pan
5.5/64
%
Colter
Vitavax
None
56
5870
52.3
81.7
11.5
6.7
Colter
Baytan/Captan
None
39
6010
52.0
85.4
9.8
4.8
Colter
Colter
Colter
Vitavax
Baytan/Captan
Vitavax
Tilt 4 oz
Tilt 4 oz
Tilt 8 oz
28
24
18
5810
6690
5990
52.3
52.9
52.3
88.8
88.2
88.3
7.6
7.9
8.1
3.6
3.9
3.6
Colter
Colter
Colter
Vitavax
Baytan/Captan
Vitavax
Folicur 4 oz
Folicur 4 oz
Folicur 8 oz
14
8
4
6130
5650
6120
52.6
52.5
52.3
89.9
89.8
89.4
6.9
6.9
7.2
3.2
3.3
3.4
Colter
Colter
Colter
Colter
Baytan/Captan
Vitavax
Baytan/Captan
Vitavax
Alto 10 gm
Alto 20 gm
Alto 20 gm
Alto 40 gm
9
4
4
3
6690
5720
6570
6570
52.1
53.1
52.6
52.9
86.6
90.5
89.0
88.5
8.9
6.8
7.4
8.0
4.4
2.7
3.6
3.5
78Ab10274
78Ab10274
Vitavax
Vitavax
None
Tilt 4 oz
0
0
3880
3580
53.5
52.1
88.3
84.8
7.0
9.0
4.7
6.1
Mean
LSD (0.05)
15
10
5810
1600
52.5
0.9
8.1
2.5
4.1
1.9
CV (%)
45
12
1
87.8
4.3
3
22
32
Klamath Experiment Station
113
Table 4. Foliar Trial on Lower Lake Organic Soil. Seed treatment and foliar fungicide
effects on grain yield, test weight, lodging and reduction of lodging compared to
adjacent untreated plots of Colter and 78Ab10274 spring barley planted on Lower
Klamath Lake (LKL) organic soil in Klamath County, OR in 1996.
Entry
Variety
Foliar
Seed
Lodge
Test
Treatment
Yield
wt
lb/A
lb/bu
Lodge
reduction
%
%
1
Colter
Vitavax
None
4810
47.6
63
0
2
Colter
Baytan/Captan
None
4860
48.0
40
0
3
4
5
Colter
Colter
Colter
Vitavax
Baytan/Captan
Vitavax
Tilt 4 oz
Tilt 4 oz
Tilt 8 oz
4980
5000
5090
48.5
48.6
49.5
48
43
38
15
13
3
6
7
8
Colter
Colter
Colter
Vitavax
Baytan/Captan
Vitavax
Folicur 4 oz
Folicur 4 oz
Folicur 8 oz
5220
4630
5590
49.1
48.9
49.0
28
48
30
9
33
33
9
10
11
12
Colter
Colter
Colter
Colter
Baytan/Captan
Vitavax
Baytan/Captan
Vitavax
Alto 10 gm
Alto 20 gm
Alto 20 gm
Alto 40 gm
4920
4340
4960
4810
49.1
48.8
46.8
49.1
34
49
48
40
9
4
8
13
13
14
78Ab10274
78Ab10274
Vitavax
Vitavax
None
Tilt 4 oz
3200
3330
48.5
48.6
53
40
0
0
4700
48.6
43
10
390
1.4
NS
17
6
2
48
124
Mean
LSD (0.05)
CV (%)
114
Klamath Experiment Station
Table 5. Three-Location Summary of Spring Barley Foliar Fungicide Trial. Seed treatment
and foliar fungicide effects on barley stripe rust infestation (BSR), grain yield, test weight,
and thins of Colter spring barley planted at three locations in Klamath Co., Oregon and
Siskiyou Co., California, 1996.
Thins
Treatment
Entry
Foliar
Seed
Yield
Test wt
%
lb/A
lb/bu
6/64
5.5/64
1
Vitavax
None
50
5780
48.1
71.8
19.9
2
Baytan/Captan
None
40
5790
48.2
74.1
17.8
3
4
5
Vitavax
Baytan/Captan
Vitavax
Tilt 4 oz
Tilt 4 oz
Tilt 8 oz
22
16
11
6370
6430
6320
49.1
49.3
49.8
80.6
79.5
82.7
13.6
14.1
12.0
6
7
8
Vitavax
Baytan/Captan
Vitavax
Folicur 4 oz
Folicur 4 oz
Folicur 8 oz
8
5
2
6480
6100
6570
49.6
49.5
49.6
84.8
83.5
85.5
10.4
11.4
10.0
9
10
Vitavax
Baytan/Captan
Alto 20 gm
Alto 20 gm
2
2
6080
6530
49.8
48.2
82.2
80.5
12.5
12.9
16
0.00
9.8
0.32
6240
0.00
500
0.01
49.1
0.00
1.4
0.04
80.5
0.00
9.9
0.00
13.5
0.00
5.3
0.00
Mean
P - Value
LSD (0.05)
Trt * Location Interaction
1
BSR1
/ Average of two sites, Klamath Experiment Station and Intermountain Research and
Exension Center.
Klamath Experiment Station
115