Small Scale Seed Treatment Trials in the Klamath Basin
R.L. Dove1 1 , George Stallings 2 , and G. Chilcote l
Introduction
Seed treatment is an environmentally
safe method of protecting small grains from
seed and soil borne pathogens. The use of seed
treatments for control of a number of smut
species is universally accepted in the industry.
New products are being developed for
controlling other pathogens as well.
Imazalyl has been an effective control
against common root rot in other areas, but has
not been tested in the Klamath Basin. Common
root rot is a continuing problem in the Klamath
Basin and is especially damaging in
continuously cropped small grains. This
pathogen is favored by wet, cold springs and
improper irrigation management.
System3 is a dry seed treatment designed
to be added to seed in the seed box in addition
to standard smut and seed borne disease
treatments.
Baytan, Raxil, and Gaucho are discussed
in the previous section of this report. All
products were compared to an untreated control
in small scale experiments at the KES, and
irrigated and unirrigated Lower Klamath Lake
sites previously described.
Procedures
Two small scale seed treatment trials were
established in the Klamath Basin in 1996. Trial
1 examined the effectiveness of various seed
treatments in protecting spring seeded barley
2
from a variety of fungal pathogens using
traditional small plot techniques. Trial 2
examined the effectiveness of various rates of
Gaucho seed treatment in controlling damage
by the wheat stem maggot and other insects
using small plots.
Trial 1. Fungicide Seed Treatments
Seed of Gus barley was treated with eight
seed treatments prior to planting. Treatments
included: one rate of Baytan and Captan; one
rate of Baytan and RTU Vitavax; one rate of
Imazalyl and RTU Vitavax; two Raxil
formulations; one rate of System3; and one
RTU Vitavax treatment, which is the industry
standard. An untreated control was also
included in the trial. Treatment rates are shown
in ounce product/cwt of seed in Table 1.
All trials were arranged in a randomized
complete block design with four replications.
The trial at KES was planted on May 10.
Irrigated and unirrigated organic soil sites were
planted on May 30 and May 2, respectively.
Seed was planted one inch deep at a seeding
rate of 100 lb/acre. All plots were fertilized
with 100 lb N, 60 lb P 2 O 5 , and 44 lb S/acre at
time of seeding. Plots measured 5 x 20 feet
with a row spacing of 6 inches (10 rows).
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 using a plot combine
Associate Professor, and Research Technician, respectively, Klamath Experiment Station,
Klamath Falls, OR.
Technical Sales Representative, Gustafson Incorporated, Plano, TX.
Acknowledgments: Gustafson provided material and partial funding for these trials. Henzel Farms
provided the Klamath Co. organic soil site and crop care. The Experiment Station greatly appreciates
their support and participation.
120
Klamath Experiment Station
with a 5-foot wide header. Grain yield was
recorded for all plots. Test weight, percent
plumps, and percent thins were measured in
only one replication.
Trial 2. Gaucho Seed Treatment
Seed was treated with four rates of
Gaucho in addition to the standard rate of RTU
Vitavax. Rates of Gaucho application were
0.75, 1.0, 1.5, and 2.0 oz of material per 100 lb
seed. An untreated control was also included in
the trial. The trial was arranged in a
randomized complete block design with four
replications. Cultural practices were identical
to those described for Trial 1.
Results
Trial 1. Fungicidal Seed Treatments
There was no significant difference in
grain yield due to fungicidal seed treatment at
any site (Tables 1-3). A light infestation of
barley stripe rust occurred at all three sites in
August 1996. The infestation was not severe
enough to cause dramatic yield losses. The
occurrence of the disease was so late in the
season that the early season protection provided
by Baytan was no longer effective. A severe
mid-August frost at the unirrigated organic soil
site severely damaged heads in the mid-stage of
grain fill, resulting in substantial yield loss.
Barley stripe rust was also present in
1995, but seed treatment trials in that year did
not show any seed treatment efficacy against
barley stripe rust. As in 1996, the infestation
occurred late in the season after the expected
window of protection from Baytan was passed.
Data from the Baytan/Captan plots was lost at
the irrigated organic soil site; however, the
Baytan/RTU VT treatment was not different
than the RTU VT treatment in either yield or
quality (Table 2). When averaged across three
sites, four entries (3 through 6) had higher test
weights than the RTU VT treatment (Table 4).
Only the B aytan/RTU VT treatment had a
higher test weight than the untreated control.
Trial 2. Gaucho Seed Treatments
Gaucho seed treatment did not affect
barley grain yield at KES or the irrigated
organic soil site in 1996 (Tables 5 and 6). The
unirrigated organic soil site showed mixed
results, and due to high variability caused by
frost, no conclusion can be drawn (Table 7).
In 1994, yields of Gaucho treated plots
were significantly higher than the control at
both irrigated sites, but not at the unirrigated
site. Although infestation of wheat stem
maggot was very light in 1994, there was a low
level of Russian wheat aphid at the experiment
station and a high level of infestation of corn
leaf aphids at the irrigated organic soil site. It
appears that the Gaucho seed treatment
suppressed the populations of these insects,
resulting in higher yields. Grain quality
parameters such as test weight and percent
plumps (percent above 6/64 screen) were also
higher for the Gaucho treatment than the
control at the two organic soil sites.
Conclusions
Further testing is needed to determine
the effectiveness of these seed treatments
against the various pest species in the Klamath
Basin. Differences in yield and grain quality
due to seed treatments is often small and hard
to detect in small scale plots. Results from field
scale trials using similar treatments produced
positive results, low coefficients of variation,
and improved precision in evaluating the
efficacy of treatments. The increased labor and
time needed to conduct field-scale trials
requires that a limited number of entries be
used. The continued use of small scale testing
to identify treatments for inclusion in fieldscale trials is warranted.
Klamath Experiment Station
121
Table 1. Seed Treatment Trial (Irrigated Mineral Soil). Effect of seed treatment on grain
yield, test weight, and percent thins of spring-planted Colter barley. Plots were
established on May 8, 1996 at Klamath Experiment Station, Klamath Falls, OR.
Entry
Treatment
Yield
lb/A
Test
wt
lb/bu
6/64
Thins
5.5/64
Pan
1
2
3
Baytan @1.25 + Captan @2.0
Baytan @1.50 + Captan @2.0
Baytan @ 1.50 + RTU VT @ 6.0
3560
3180
3560
51.8
51.8
51.5
81.8
80.2
81.8
11.5
13.3
12.0
6.7
6.5
6.2
4
5
6
Imazalyl @0.25 + RTU VT @6.0
RXT @0.60
Raxil / Thiram @ 3.5
3480
3750
4040
51.8
51.8
52.9
79.1
79.3
81.7
13.7
13.9
12.3
7.2
6.8
6.0
7
8
9
System3 @4.0
RTU VT @6.0
Untreated Control
3600
3480
3610
51.8
51.6
51.4
76.7
78.0
78.2
15.3
14.8
13.9
8.0
7.2
7.9
Mean
LSD (0.05)
CV (%)
3580
NS
20
51.8
NS
1
79.6
NS
6
13.4
NS
26
6.9
NS
22
Table 2. Seed Treatment Trial (Irrigated Organic Soil). Effect of seed treatment on grain
yield, test weight, and percent thins of spring-planted Colter barley. Plots were
established on May 30, 1996 on irrigated organic soil, in Klamath County, OR.
Treatment
Entry
6/64
Thins
5.5/64
Pan
1 Baytan @1.25 + Captan @2.0
2 Baytan @1.50 + Captan @2.0
3 Baytan @ 1.50 + RTU VT @ 6.0
4780
47.6
77.7
15.2
7.2
4 Imazalyl @0.25 + RTU VT @6.0
5 RXT @0.60
6 Raxil / Thiram @ 3.5
4940
5330
4570
47.6
48.0
48.6
76.8
79.9
76.9
15.4
13.5
14.8
7.8
6.6
8.3
7 System3 @4.0
8 RTU VT @6.0
9 Untreated Control
4700
4530
4930
48.1
47.8
47.8
77.9
74.0
80.5
14.5
17.7
13.0
7.6
8.3
6.5
4830
NS
11
47.9
NS
2
77.7
NS
4
14.9
2.7
12
7.5
NS
15
Mean
LSD (0.05)
CV (%)
122
Yield
lb/A
Test
wt
lb/bu
Klamath Experiment Station
Table 3. Seed Treatment Trial (Unirrigated Organic Soil). Effect of seed treatment on
grain yield, test weight, and percent thins of spring-planted Colter barley. Plots were
established on May 2, 1996 on unirrigated organic soil, in Klamath County, OR.
Entry
Treatment
Yield
Test
wt
lb/A
lb/bu
6/64
Thins
5.5/64
Pan
1
2
3
Baytan @1.25 + Captan @2.0
Baytan @1.50 + Captan @2.0
Baytan @ 1.50 + RTU VT @ 6.0
1590
1140
1110
44.5
43.9
44.3
58.1
59.8
62.0
22.6
21.7
20.4
19.3
18.5
17.6
4
5
6
Imazalyl @0.25 + RTU VT @6.0
RXT @0.60
Raxil / Thiram @ 3.5
1350
1910
1440
44.8
45.8
44.5
57.0
55.8
52.6
23.8
24.3
25.4
19.2
19.8
21.9
7
8
9
System3 @4.0
RTU VT @6.0
Untreated Control
1560
1520
1310
43.8
44.8
43.3
51.2
51.8
55.3
26.2
25.0
23.2
22.6
23.2
21.5
Mean
LSD (0.05)
CV (%)
1440
NS
11
44.4
NS
2
56.0
NS
4
23.6
2.7
12
20.4
NS
15
Table 4. Three-location summary of Seed Treatment Trial. Effect of seed treatment on grain
yield, test weight, and percent thins of spring-planted Colter barley. Plots were
established at three sites in Klamath County, OR in 1996.
Entry
Treatment
Yield
lb/A
Test
wt
lb/bu
6/64
Thins
5.5/64
Pan
1
Baytan @1.25 + Captan @2.0
2
3
Baytan @1.50 + Captan @2.0
Baytan @ 1.50 + RTU VT @ 6.0
3150
73.8
15.9
10.3
17.6
4
5
6
Imazalyl @0.25 + RTU VT @6.0
RXT @0.60
Raxil / Thiram @ 3.5
3260
3660
3350
71.0
71.6
70.4
17.6
17.3
17.5
11.4
11.1
12.1
19.2
19.8
21.9
7
8
9
System3 @4.0
RTU VT @6.0
Untreated Control
3290
3180
3280
68.6
67.9
71.3
18.7
19.2
16.7
12.8
12.9
12.0
22.6
23.2
21.5
Mean
LSD (0.05)
CV (%)
3310
NS
17
70.7
0.8
2
17.6
NS
7
11.8
NS
16
20.8
1.7
17
Klamath Experiment Station 123
Table 5. 1996 Gaucho Seed Treatment (Irrigated Mineral Soil). Effect of
Gaucho seed treatment on grain yield, test weight, and percent thins of
Colter barley planted on May 8, 1996 on irrigated mineral soil at
Klamath Experiment Station, OR.
Test
Entry Treatment
1
2
3
4
5
Yield
lb/A
wt
lb/bu
Control
Gaucho @ 0.75
Gaucho @ 1.00
Gaucho @ 1.50
Gaucho @ 2.00
5120
4790
4640
4810
4700
Mean
LSD (0.05)
CV (%)
4810
NS
9
Thins
6/64
5.5/64
Pan
52.4
53.0
52.9
52.8
52.4
85.3
90.0
89.4
87.3
87.5
9.1
6.5
6.9
7.8
8.0
5.7
3.5
3.6
4.9
4.5
52.7
NS
1
87.9
2.6
2
7.7
1.4
12
4.4
1.3
19
Table 6. 1996 Gaucho Seed Treatment (Irrigated Organic Soil). Effect of
Gaucho seed treatment on grain yield, test weight, and percent thins of
Colter barley. Plots were established on May 30, 1996 on irrigated
organic soil, in Klamath County, OR.
Entry Treatment
1
2
3
4
5
124
Test
wt
lb/bu
Yield
lb/A
6/64
Thins
5.5/64
Pan
Control
Gaucho @ 0.75
Gaucho @ 1.00
Gaucho @ 1.50
Gaucho @ 2.00
4410
4840
4390
4070
4080
47.9
47.8
47.1
47.8
46.4
74.8
74.9
73.4
71.5
69.5
16.6
16.4
17.9
18.6
19.9
8.7
8.6
8.7
9.9
10.6
Mean
LSD (0.05)
CV (%)
4360
NS
11
47.4
0.9
1
72.8
NS
6
17.9
NS
14
9.3
NS
20
Klamath Experiment Station
Table 7. 1996 Gaucho Seed Treatment (Unirrigated Organic Soil). Effect of
Gaucho seed treatment on grain yield, test weight, and percent thins of
Colter barley. Plots were established on May 2, 1996, on unirrigated
organic soil, in Klamath County, OR.
Test
Entry Treatment
1
2
3
4
5
Thins
Yield
lb/A
wt
lb/bu
6/64
5.5/64
Control
Gaucho @ 0.75
Gaucho @ 1.00
Gaucho @ 1.50
Gaucho @ 2.00
2060
1710
1670
2020
2140
46.4
44.4
46.0
46.9
45.1
62.6
59.9
61.3
63.6
61.6
20.4
22.2
21.6
19.9
21.2
17.0
17.9
17.1
16.5
17.2
Mean
LSD (0.05)
CV (%)
1920
530
18
45.8
2.4
3
61.8
8.0
8
21.1
3.2
10
17.1
5.0
19
Pan
Table 8. Three-location Summary of Gaucho Trial. Effect of seed treatment
on grain yield, test weight, and percent thins of spring-planted Colter
barley. Plots were established at three sites in Klamath County, OR.
Entry Treatment
1
2
3
4
5
Control
Gaucho @ 0.75
Gaucho @ 1.00
Gaucho @ 1.50
Gaucho @ 2.00
Mean
LSD (0.05)
CV (%)
Yield
lb/A
3860
3780
3570
3630
3640
Test
wt
lb/bu
48.9
48.4
48.7
49.2
48.0
3700
NS
11
48.6
NS
2
6/64
Thins
5.5/64
Pan
74.2
74.9
74.7
74.1
72.9
15.4
15.0
15.5
15.4
16.4
10.5
10.0
9.8
10.4
10.8
74.2
NS
5
15.5
NS
13
10.3
NS
21
Klamath Experiment Station
125