Klamath Experiment Station
Control of Barley Stripe Rust in the Klamath Basin, 1997
Randy Dovel', Steve Orloff, Greg Chilcote l , and Don Kirby'
A
bstract
The effectiveness of three foliar fungicides, either with or without Baytan seed
treatment was evaluated at Klamath Experiment
Station (KES), a mineral soil site, and at an
irrigated organic soil site at the Intermountain
Research and Extension Center (IREC) in
Siskiyou Co., California. Colter spring barley
was treated with Tilt, Folicur, and Alto with either
a standard seed treatment (Vitavax RTU) or with
Baytan. Two rates of Tilt and Folicur were
included at both sites and three rates of Alto were
included in the Oregon trials. Foliar fungicides
were applied to plots at approximately 50 percent
head emergence. Applications in 1996 were
made on July 3 at KES and June 26 at IREC.
Barley stripe rust (BSR) infection at time of
fungicide application was less than 5 percent at
both sites. Applications in 1997 were made on
July 3 at KES and June 26 at IREC. BSR
infection at time of fungicide application in 1997
was less than 1 percent at IREC and over 5
percent at KES. Foliar fungicide applications
significantly reduced BSR infection at both
locations in both 1996 and 1997. There was no
significant difference in BSR infection between the
two seed treatments when foliar fungicides were
applied. Both Folicur and Alto application
resulted in similar BSR infection levels, which
were lower than in Tilt treated plots at both KES
and IREC in 1996. Similar levels of control were
seen for all three fungicides in 1997. Almost all
foliar fungicide treatments resulted in significantly
higher yields than the untreated control. Grain
yield and BSR infection were highly correlated at
IREC in both years and at KES in 1997. Foliar
fungicide application at IREC resulted in an
average increase in production of 1430 and 1160
lb/acre in 1996 and 1997, respectively. Foliar
fungicide application at KES resulted in an
average increase in production of 250 and 850 lb/
acre in 1996 and 1997, respectively. There was
no difference in grain yield due to seed treatment.
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
Klamath Lake leases in 1994, but laboratory
confirmation of the presence of the disease was
not possible. Economically significant occurrences of the disease were seen for the first time
in the Klamath Basin in 1995. Significant losses
from BSR infection occurred throughout the
Klamath Basin in 1996 and 1997.
The effect of BSR on barley yield can he
devastating, with up to 85 percent yield reduction
reported from Bolivia and Mexico. In general,
yield reduction in the United States has been less
I/ Associate Professor, and Research Technician, respectively, Klamath Experiment Station, Klamath
Falls, OR.
21 Farm Advisor, Siskiyou Co. and Acting Superintendent/Research Associate, Intermountain Research and
Extension Center. respectively, University of California, Tulelake, CA.
116 Klamath Experiment Station 1997
Klamath Experiment Station
Control of Barley Stripe Rust in the Klamath Basin, 1997
than in Latin America. However, the cool
moist spring conditions of the Pacific Northwest could provide an ideal environment for
BSR and appropriate precautions should be
taken.
Few winter varieties and no commercially available spring barley varieties are
resistant to this pathogen. Breeding programs
at Oregon State University (OSU), University
of California (UC) Davis, Washington State
University (WSU), and USDA research
centers in Idaho are all working to develop
resistant spring and winter varieties, but seed
of BSR-resistant varieties will not be available
in significant quantities for several years. Until
resistant varieties are available, producers
must rely on chemical control of the disease.
Chemical fungicides may be applied
either as a seed treatment or as a postemergence foliar spray. Baytan is a fungicidal
seed treatment which is effective in controlling
early-season infection by BSR. Baytan has
provided protection against BSR infection for
5 to 9 weeks after emergence. In areas where
early infection occurs, Baytan has been
effective in reducing BSR infection and
increasing yields. Baytan has been included in
several trials in the Klamath Basin to test its
effectiveness against other pathogens for the
last 4 years. In the absence of BSR, Baytan
has not increased yields compared to 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 and 1997. Folicur may
be applied as late as 50 percent head emergence.
Alto is another new fungicide that may 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 produce interactive effects. Consequently, relative effectiveness of Baytan seed treatment and foliar fungicides in various combinations
was examined in three locations in the Klamath Basin
in 1996 and 1997.
Procedures
The effectiveness of three foliar fungicides
either with or without Baytan seed treatment was
evaluated at a mineral soil site at the Klamath Experiment Station (KES) and an irrigated organic soil site
in Siskiyou Co., California , the Intermountain Research and Extension Center (IREC). Colter spring
barley was treated with Tilt, Folicur, and Alto with
either a standard seed treatment (Vitavax RTU) or
with Baytan. Two rates of Tilt and Folicur were
included at all sites and three rates of Alto were
included in the Oregon trials (Table 1).
Foliar fungicides were applied to plots at
approximately 50 percent head emergence. Applications in 1996 were made on July 3 at KES and June
26 at IREC. BSR infestation at time of fungicide
application was less than 5 percent at both sites.
Applications in 1997 were made on July 3 at KES
and June 26 at IREC. BSR infection at time of
fungicide application in 1997 was < 1 percent at
IREC and > 5 percent at KES.
Plots measured 15 x 40 feet, with a row
spacing of 6 inches. BSR infection was recorded for
all plots at KES and IREC. The trial at KES was on
land planted in potatoes the previous year. Soils at
Klamath Experiment Station 1997 117
Klamath Experiment Station
Control of Barley Stripe Rust in the Klamath Basin, 1997
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. All sites were sprinkler irrigated.
All trials were arranged in a randomized complete
block design with four replications. In 1996, the
trials at KES and IREC were planted on April 20
and May 5, respectively. In 1997, planting dates
were April 20 and May 7 for IREC and KES,
respectively. Seed was planted 1 inch deep at a
seeding rate of 100 lb/acre. All plots received 50
lb N. 30 lb P 2 O 5 , and 22 lb S/acre by broadcast
application before planting and 30 lb N, 18 lb
P 2 0 6 , and 13 lb S/acre banded at planting. 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, percentage of
plumps, and percentage of thins were measured in
all replications.
Results
Foliar fungicide application significantly (P
= 0.05) reduced BSR infection at both locations
in both 1996 and 1997 (Tables 2, 3, 5, and 6). In
plots not treated with a foliar fungicide, BSR
infection of Baytan-treated plots was lower than
Vitavax-treated plots at KES in 1996 and at
IREC in 1997 (Tables 3 and 5). However, slightly
lower BSR infection did not result in increased
grain yield in either instance. There was no
significant difference in BSR infection between the
two seed treatments when foliar fungicides were
applied. Both Folicur and Alto application
resulted in similar BSR infection levels, which
118 Klamath Experiment Station 1997
were lower than in Tilt treated plots at both KES
and IREC in 1996. Similar levels of control were
seen for all three fungicides in 1997. The higher
rate of Tilt resulted in better disease control at
KES in both years and at IREC in 1996. In
contrast, the higher rates of Folicur did not result
in lower levels of infection at either site. There
was no difference in BSR infection at KES from
different rates of Alto application in 1996, but the
40 gm rate was superior to the lower rates in
997. There were virtually no BSR pustules
found in foliar fungicide treated plots at IREC in
1997. Despite differences in disease suppression
from foliar fungicide treatment, there was little
difference in yield among treated plots. However,
almost all foliar fungicide treatments resulted in
significantly higher yields than the untreated
control.
Grain yield and BSR infection were highly
correlated at IREC in both years and at KES in
1997. However, yield increases from BSR
suppression at KES in 1997 were not as impressive as at IREC (Table 5). Foliar fungicide
application at IREC resulted in an average
increase in production of 1430 and 1160 lb/acre
in 1996 and 1997, respectively (Tables 2 and 3).
Foliar fungicide application at KES resulted in an
average increase in production of 250 and 850 lb/
acre in 1996 and 1997, respectively (Tables 5
and 6). Although foliar fungicide application
increased grain yield, there was no difference in
grain yield due to seed treatment.
Grain quality was positively affected by
foliar fungicide application at both sites. At IREC,
test weight increased from an average of 46.1 lb/
bu without foliar fungicide to 48.2 lb/bu, when
averaged across all foliar fungicide treatments and
years (Table 4). At KES, test weight increased
Klamath Experiment Station
Control of Barley Stripe Rust in the Klamath Basin, 1997
from an average of 50.0 lb/bu without foliar
fungicide to 50.9, when averaged across all foliar
fungicide treatments and years (Table 7). Plumps
increased from 79 percent to over 85 percent
due to fungicide application at KES (Table 7).
There was a noticeable decrease in lodging due
to fungicide application at another experimental
site in 1996 and in commercial fields in 1997.
Application of foliar fungicides was
economically beneficial at IREC in both years and
at KES in 1997. An average increase in yield of
1,000 lb/acre due to foliar fungicide application
would result in an additional $50/acre in net sales
with a grain price of $100/ton. Fungicide and
application costs vary but should not exceed $35/
acre and can be as low as $13/acre.
Klamath Experiment Station 1997 119
Klamath Experiment Station
Table 1. Foliar fungicide trial treatments, KES, Klamath Falls, OR, and IREC, Tulelake, CA.
Location
IREC
KES
Treatment
Variety
seed
foliar
Colter
Colter
Colter
Colter
Colter
Colter
Colter
Colter
Colter
Colter
Colter
Colter
Vitavax
Baytan/Captan
Vitavax
Baytan/Captan
Vitavax
Vitavax
Baytan/Captan
Vitavax
Baytan/Captan
Vitavax
Baytan/Captan
Vitavax
None
None
Tilt 4 oz/acre
Tilt 4 oz/acre
Tilt 8 oz/acre
Folicur 4 oz/acre
Folicur 4 oz/acre
Folicur 8 oz/acre
Alto 10 g/acre
Alto 20 g/acre
Alto 20 g/acre
Alto 40 g/acre
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Table 2. Fungicide trial: seed treatment and foliar fungicide effects on BSR infection, grain yield,test
weight, and thins of Colter spring barley planted at IREC, Tulelake, CA, 1996.
Entry
seed
Treatment
foliar
BSR
Yield
Test
wt
lb/A
lb/bu
Thins
5.5/64
6/64
1
2
Vitavax
Baytan/Captan
None
None
44
40
6650
6490
44.0
45.0
54.9
60.1
34.4
28.5
3
4
5
Vitavax
Baytan/Captan
Vitavax
Tilt 4 oz/acre
Tilt 4 oz/acre
Tilt 8 oz/acre
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/acre
Folicur 4 oz/acre
Folicur 8 oz/acre
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 g/acre
Alto 20 g/acre
0
0
8170
8040
48.0
45.0
80.1
75.0
15.4
17.0
12
10
60
7720
330
3
46.0
2.0
2
74.8
6.6
6
18.5
4.4
17
Mean
LSD (P= 0.05)
CV (%)
120 Klamath Experiment Station 1997
Klamath Experiment Station
Table 3. Fungicide trial: seed treatment and foliar fungicide effects on BSR infection, grain yield, test weight,
and thins of Colter spring barley planted at IREC, Tulelake, CA, 1997.
Yield
Test
wt
lb/A
lb/bu
54
64
6510
6500
47.7
47.0
Treatment
Entry
seed
foliar
BSR
1
2
Vitavax
Baytan/Captan
None
None
3
4
5
Vitavax
Baytan/Captan
Vitavax
Tilt 4 oz/acre
Tilt 4 oz/acre
Tilt 8 oz./acre
0
0
0
7740
7470
7580
49.8
49.9
48.1
6
7
8
Vitavax
Baytan/Captan
Vitavax
Folicur 4 oz/acre
Folicur 4 oz/acre
Folicur 8 oz/acre
0
0
0
7710
7810
7650
50.2
49.8
50.1
9
10
Vitavax
Baytan/Captan
Alto 20 g/acre
Alto 20 g/acre
0
0
7570
7800
49.4
48.7
12
4
22
7430
520
5
49.1
NS
4
Mean
LSD (P= 0.05)
CV (%)
Klamath Experiment Station 1997 121
Klamath Experiment Station
Table 4. Fungicide trial: seed treatment and foliar fungicide effects on BSR infection, grain yield, test
weight, and thins of Colter spring barley planted at IREC, Tulelake, CA, 1996 and 1997.
Entry
seed
Treatment
foliar
2
Vitavax
Baytan/Captan
None
None
3
4
5
Vitavax
Baytan/Captan
Vitavax
Tilt 4 oz/acre
Tilt 4 oz/acre
Tilt 8 oz/acre
6
7
8
Vitavax
Baytan/Captan
Vitavax
Folicur 4 oz/acre
Folicur 4 oz/acre
Folicur 8 oz/acre
9
10
Vitavax
Baytan/Captan
Alto 20 g/acre
Alto 20 g/acre
Mean
LSD (P= 0.05)
Yr x Trt Interacretion
CV (%)
122 Klamath Experiment Station 1997
Yield
Test
wt
lb/A
lb/bu
49
52
6580
6490
46.0
46.1
8
4
2
8020
7540
7730
48.1
48.2
48.2
7900
7920
7830
48.6
48.5
48.8
0
0
7870
7920
48.5
47.0
12
3
7580
310
NS
4
47.8
1.6
NS
3
BSR
23
Klamath Experiment Station
Table 5. Fungicide trial: seed treatment and foliar fungicide effects on BSR infection, grain yield, test weight,
and thins of Colter spring barley planted at KES, Klamath Falls, OR, 1996.
seed
Treatment
foliar
BSR
Yield
Test
wt
lb/A
lb/bu
6/64
Thins
5.5/64
pan
Vitavax
Baytan/Captan
None
None
56
39
5870
6010
52.3
52.0
81.7
85.4
11.5
9.8
6.7
4.8
Vitavax
Baytan/Captan
Vitavax
Tilt 4 oz/acre
Tilt 4 oz/acre
Tilt 8 oz/acre
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
Vitavax
Baytan/Captan
Vitavax
Folicur 4 oz/acre
Folicur 4 oz/acre
Folicur 8 oz/acre
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
Baytan/Captan
Vitavax
Baytan/Captan
Vitavax
Alto 10 g/acre
Alto 20 g/acre
Alto 20 g/acre
Alto 40 g/acre
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
15
10
45
5810
600
12
52.5
0.9
1
87.8
4.3
3
8.1
2.5
22
4.1
1.9
32
Mean
LSD (P= 0.05)
CV (%)
Klamath Experiment Station 1997 123
Klamath Experiment Station
Table 6. Fungicide trial: seed treatment and foliar fungicide effects on BSR infection, grain yield, test
weight, and thins of Colter spring barley planted at KES, Klamath Falls, OR, 1997.
seed
Treatment
foliar
BSR
Yield
Test
wt
lb/A
lb/bu
6/64
Thins
5.5/64
pan
Vitavax
Baytan/Captan
None
None
68
65
3270
3690
47.1
48.5
72.7
76.7
14.6
12.9
12.7
10.4
Vitavax
Baytan/Captan
Vitavax
Tilt 4 oz/acre
Tilt 4 ozJacre
Tilt 8 oz/acre
52
48
28
4410
4300
4410
48.4
48.4
50.5
78.6
78.4
82.1
12.0
12.0
10.8
9.4
9.7
7.1
Vitavax
Baytan/Captan
Vitavax
Folicur 4 az/acre
Folicur 4 oz/acre
Folicur 8 oz/acre
33
14
24
4540
3730
4030
49.0
48.9
49.0
82.0
80.6
80.3
10.9
12.1
12.0
7.2
7.3
7.7
Baytan/Captan
Vitavax
Baytan/Captan
Vitavax
Alto 10 g/acre
Alto 20 g/acre
Alto 20 g/acre
Alto 40 g/acre
32
24
28
8
4060
4190
4480
5190
49.1
50.4
49.2
50.3
84.1
85.1
78.3
92.4
9.8
9.7
12.5
5.0
6.1
5.2
9.2
2.6
38
24
44
4180
680
11
49.0
NS
3
82.4
9.0
8
10.4
4.0
27
7.3
5.1
50
Mean
LSD (P= 0.05)
CV (c7c)
124 Klamath Experiment Station 1997
Klamath Experiment Station
Table 7. Fungicide trial: seed treatment and foliar fungicide effects on BSR infection, grain yield, test
weight, and thins of Colter spring barley planted at KES, Klamath Falls, OR, 1996 and 1997.
seed
Treatment
foliar
BSR
Yield
Test
wt
%
lb/A
lb/bu
6/64
Thins
5.5/64
pan
%
Vitavax
Baytan/Captan
None
None
62
52
4570
4850
49.7
50.3
77.1
80.8
13.1
11.4
9.8
7.7
Vitavax
Baytan/Captan
Vitavax
Tilt 4 ozJacre
Tilt 4 ozlacre
Tilt 8 ozlacre
40
36
23
5110
5500
5200
50.3
50.6
51.4
83.6
83.2
85.2
9.8
10.0
9.5
6.6
6.8
5.3
Vitavax
Baytan/Captan
Vitavax
Folicur 4 ozlacre
Folicur 4 oz/acre
Folicur 8 oz/acre
23
11
14
5330
4690
5070
50.8
50.7
50.6
85.8
85.2
84.8
8.9
9.5
9.6
5.3
5.3
5.6
Baytan/Captan
Vitavax
Baytan/Captan
Vitavax
Alto 10 g/acre
Alto 20 g/acre
Alto 20 g/acre
Alto 40 g/acre
21
14
16
6
5380
4950
5530
5880
50.6
51.8
51.1
51.6
85.4
87.8
85.1
90.5
9.4
8.2
9.2
6.5
5.3
4.0
5.6
3.1
29
13
NS
46
5080
690
NS
13
50.7
1.2
NS
3
83.9
5.5
NS
7
9.9
2.5
NS
26
6.2
3.1
NS
50
Mean
LSD (P= 0.05)
Yr x Trt Interacretion
CV (%) •
Klamath Experiment Station 1997 125