Foramsulfuron Effects on Emergence of
Seeded Turf-Type Bermudagrass
D. Kopec, J. Gilbert, M. Pessarakli, D. Kerr and J. Spence
University of Arizona
Tucson, Arizona
Abstract
Several new sulfonylurea products have (or are being) brought to market for use
in turf. One use of these products is for removing ryegrass from overseeded
bermudagrass, since perennial ryegrass has become too persistent due to
improvements in heat, drought, and close mowing tolerance. The soil half life of
sulfonylurea is greatly increased in high pH soils, which are typical in the
southwest. Superintendents may need to re-establish seeded bermudagrass after
use of a S.U. transition agent if the underlying bermudagrass is sparse. With
this in mind, a replicated field trial was conducted in summer 2004 to evaluate
three rates of foramsulfuron (0.4, 0.8, 1.2 ounce /product/1000 ft2) herbicide at
0, 7, 14, and 28 days after seeding. Foramsulfuron is sold as Revolver.
Revolver applied at time of seeding (0DAS) and 1 week after seeding (7 DAS)
caused the greatest amounts of bermudagrass suppression in terms of
bermudagrass plot cover and visible seedling vigor. When applied (7 DAS),
bermuda cover (averaged over all three applied rates of Revolver) at 21, 28,
and 36 DAS was 8%, 22% and 32% bermuda cover, respectfully, versus NTC
mean values of 22, 49 and 54% cover, respectively. The second greatest degree
of Bermuda suppression occurred from Revolver applied at the day of seeding (0
DAS). The effects lasted up until and included the end of the test on 29 Sept (36
DAS). When averaged over all 3 applied rates of Revolver, percent plot
bermudagrass cover at 21, 28, and 36 DAS was 10%, 30% and 40% respectively
for the 0 DAS treatments. The NTC cover for these same dates was 22%, 50%
and 53% respectively. Vigor visual scores were minimal as well for all rates
applied at (0 DAS) and at (7 DAS). Plots remained stunted up to 36 DAS for
Revolver turfs applied at (7 DAS) and (0 DAS). Application at the time of
seeding (0 DAS) resulted in more bermudagrass plot cover than if applied at (7
DAS). Rate reduction responses were realized only for Revolver application
timings made at 0 DAS and 7 DAS (Table 1, 5, Figs. 1-4). No rate responses
resulted for Revolver when applied at 14 DAS, 28 DAS. In conclusion, Revolver
was safest when applied 14 DAS or later, with little rate effects.
Introduction
Foramsulfuron (Revolver) has been successfully tested as a transition agent in removing perennial ryegrass from
overseeded bermudagrass turf. Sulfonylurea compounds brought to the market or that are in development in the last
five years vary tremendously in their soil half-life. Many compounds have much shorter half-lives than the original
compounds such as metsulfuron and chlorsulfuron. Degradation by hydrolysis is also pH dependent and high soil pH
conditions increase soil half-life residuals considerably.
__________________________________
This is a part of the University of Arizona College of Agriculture2004 Turfgrass and Ornamental Research Report, index at:
http://cals.arizona.edu/pubs/crops/az1359/
Using a sulfonyl urea product for inducing spring turf transition is generally safe on existing bermudagrass.
However, in areas which have no or minimal underlying bermudagrass, seeding bermudagrass into the canopy is on
option turf managers may select to establish/increase bermudagrass cover. With this question in mind, a field trial
was conducted to evaluate the affects of Revolver herbicide on the emergence of newly seeded bermudagrass seed.
Materials and Methods
Three rates of Revolver, 0.4, 0.8, 1.2 ounce product per thousand square feet (hereafter as ounce/p/M) were applied
to newly seeded ‘Princess’ bermudagrass. The seed was sewn on a prepared base soil seedbed that was lightly rototilled and raked. Seed was applied at 1.0 lb. PLS/M to the entire test area on August 21, 2004. The test site was
irrigated for germination and emergence starting August 25, 2005. All three rates of Revolver were applied at the
following times: (1) At the day of seeding, (2) seven days after seeding, (3) fourteen days after seeding, and (4)
twenty-eight days after seeding. Revolver was applied using a Co2 pressure backpack sprayer using 8004 nozzles at
a solution delivery rate of 45 GPA. Each treatment appeared four times in a RCB field design. Plots were evaluated
for percent bermudagrass plot cover (1%-100%) on 7, 14, 21, 29 of September and for plant vigor (1-6 subjective
scale) on 14, 21 29 of September.
The timing/application structure utilized in this test allowed for determining any inhibition of bermudagrass
emergence based on herbicide application (safety window).
All data was analyzed using the analysis of variance technique using SAS mainframe software. A main ANOVA
was performed for the entire data matrix (application timing and Revolver rate combinations) as well as for
Revolver rates for each application date (days after seeding)
Since bermudagrass response data was collected on separate days from the day of herbicide application, standard
LSD values were computed as the treatment mean separation statistic. The significance alpha level was P = 0.05.
The non treated control (NTC) was included in the ANOVA, since the actual percent bermudagrass cover is the
critical biological component [rather than percent reduction as 1 – (Treated response / NTC response) x 100].
Treatment means and LSD values (where applicable) are presented for the entire data set (Table 1) and for each day
of application of Revolver after seeding (All remaining Tables, all Figures).
Results and Discussion
The herbicide treatments did affect the emergence of ‘Princess’ seeded bermudagrass to various degrees up to and
including 36 days after seeding. This was rate dependent and based also on the number of days after seeding that the
Revolver was applied (Table 1).
When comparing NTC plot coverage to that of the treated turfs in Table 1, the following conditions resulted:
At 14 DAS (7 Sept 2004), treatments of Revolver applied at 7 DAS caused slightly less emergence then when
applied at the time of seeding (0 DAS). The NTC averaged 10.3% bermuda cover; while treatments applied 7 DAS
averaged 1.5 – 2.0% bermuda cover. At 7 September, Revolver applied at the time of seeding (0 DAS) had 4.0 – 6.3
% bermudagrass plot cover.
From 7 Sept to 29 Sept, the 7 DAS application of Revolver caused the greatest initial and lagging reduction in
emergence/cover of bermudagrass. On 14, 21, 29 of September, Revolver applied (7 DAS) had about 20%, 45-50%,
and 60% relative cover of that of the NTC turfs. On 14, 21, 29 of September, the percent plot cover bermuda of
NTC was 22, 49 and 53% actual ground cover, respectively. Note again that the % bermudagrass cover was least for
the entire test evaluation period from the (7 DAS) Revolver application. This data shows that a Revolver application
at, or near actual emergence (after germination has begun) had a greater affect than a Revolver application before
actual germination had begun (applied @ 0 DAS).
Revolver applied (7 DAS) had only 4.5 – 7.5% bermudagrass plot cover at 21 DAS (14 Sept), while the NTC
averaged 22.2% bermuda plot cover. Note that the bermudagrass cover for Revolver applied at time of seeding (0
DAS) had slightly more bermudagrass cover (7.0-13.3%) at that the same time (21 DAS = 14 September) (Table 1).
By 28 DAS (21 Sept), bermudagrass plot cover for Revolver applied at 14 DAS was 41%, 58%, 45%, which was
essentially similar to that of the NTC (50%). Seedling vigor ratings on 21 Sept were similar to those of the NTC as
well. Likewise, by 29 Sept (36 DAS), there was no affect of Revolver on emergence/plot cover for the 14 DAS
treatments. Therefore, when applied 14 DAS, Revolver (at all three rates) caused a one-time decrease in
bermudagrass cover at 21 DAS.
There was no affect of Revolver (at any rates) when applied 28 DAS, as bermuda plot cover was essentially
identical to that of the NTC turf (54%).
Conclusions
1.
Revolver applied at time of seeding (0 DAS) and 1 week after seeding (7 DAS) caused the greatest amounts of
bermudagrass suppression in terms of bermudagrass plot cover and visible seedling vigor. The 7 DAS
treatments of Revolver resulted in the least bermudagrass plot establishment, throughout the entire test. When
applied at (7 DAS), bermuda cover (when averaged over all three applied rates of Revolver) 21, 28, and 36
DAS was 8%, 22% and 32% bermuda cover, respectfully, versus NTC mean values of 22, 49 and 54% cover,
respectively.
2.
The second greatest degree of bermuda suppression occurred from Revolver applied at the day of seeding (0
DAS). The effects lasted up until and included the end of the test on 29 Sept (36 DAS). When averaged over all
3 applied rates of Revolver, percent plot bermudagrass cover at 21, 28, and 36 DAS was 10%, 30% and 40%
respectively. The NTC cover for these same dates was 22%, 50% and 53% respectively. Vigor visual scores
were minimal as well for all rates applied at (0 DAS). Plots remained stunted up to 36 DAS. Only the turfs
treated at 7 DAS remained more “visually” stunted at 36 DAS.
3.
Application at the time of seeding (0 DAS) resulted in more bermudagrass plot cover than if applied at (7 DAS)
(Table 1).
4.
Rate reduction responses were realized only for Revolver application timings made at 0 DAS and 7 DAS (Table
1, 5, Figs. 1-4). No rate responses resulted for Revolver when applied at 14 DAS, 28 DAS.
5.
In conclusion, Revolver was safest when applied 14 DAS or later, with little rate effects.
TEXT FN: TADGERM04text.doc / tosh
TABLES and Figures FN: TADGERM.xls / tosh
Search words:
Tads foramsulfron Bermuda bermudagrass Princess emergence LSD
%-Bermudagrass
Figure 1. %-Bermudagrass Cover as
affected by 'Revolver' applied AT SEEDING
ab b b a
60
b b b a
40
B BC C A
20
B B B A
0
14(14)
21(21)
28(28)
36(36)
Days After Seeding(days after appl.)
Revolver @ 0.4 oz/M
Revolver @ 0.8 oz/M
Revolver @ 1.2 oz/M
Non-Treated Control
* 'Princess' Bermudagrass seeded on: August 24, 2004
Figure 2. %-Bermudagrass Cover as affected by
'Revolver' applied 7 DAYS AFTER SEEDING
% -Bermudagrass
60
40
20
0
14(7)
21(14)
28(21)
36(29)
Days After Seeding(days after appl.)
Revolver @ 0.4 oz/M
Revolver @ 0.8 oz/M
Revolver @ 1.2 oz/M
Non-Treated Control
* 'Princess' Bermudagrass seeded on: August 24, 2004
Figure 3. %-Bermudagrass Cover as affected by
'Revolver' applied 14 DAYS AFTER SEEDING
70
% -Bermudagrass
60
50
40
30
20
b ab ab a
10
a a a a
0
14(0)
21(7)
28(14)
36(22)
Days After Seeding(days after appl.)
Revolver @ 0.4 oz/M
Revolver @ 0.8 oz/M
Revolver @ 1.2 oz/M
Non-Treated Control
* 'Princess' Bermudagrass seeded on: August 24, 2004
Figure 4. %-Bermudagrass Cover as affected by
'Revolver' applied 28 DAYS AFTER SEEDING
% -Bermudagrass
60
40
20
0
14(-14)
21(-7)
28(0)
36(8)
Days After Seeding(days from appl.)
Revolver @ 0.4 oz/M
Revolver @ 0.8 oz/M
Revolver @ 1.2 oz/M
Non-Treated Control
* 'Princess' Bermudagrass seeded on: August 24, 2004
Table 1. Percent Bermudagrass cover and seedling Vigor as affected by 'Revolver' applied at seeding and 7,
14 & 28 days after seeding. University of Arizona, Karsten Turfgrass Research Facility. Tucson, AZ.
Treatment
days after seeding
Revolver @ 0.4 oz/M (AT SEEDING)
Revolver @ 0.8 oz/M (AT SEEDING)
Revolver @ 1.2 oz/M (AT SEEDING)
7-Sep
14
6.3
5.5
4.0
%-berm
14-Sep
21-Sep
21
28
13.3
34.3
10.0
29.3
7.0
25.5
29-Sep
36
44.3
38.3
34.3
14-Sep
21
2.5
1.8
2.0
vigor
21-Sep
28
2.5
2.8
2.8
29-Sep
36
2.0
2.0
2.0
Revolver @ 0.4 oz/M (7 DAS)
Revolver @ 0.8 oz/M (7 DAS)
Revolver @ 1.2 oz/M (7 DAS)
2.0
2.0
1.5
7.5
5.0
4.5
28.0
20.8
18.0
35.0
33.5
27.5
2.0
1.3
1.3
2.3
1.5
2.0
1.8
1.5
1.0
Revolver @ 0.4 oz/M (14 DAS)
Revolver @ 0.8 oz/M (14 DAS)
Revolver @ 1.2 oz/M (14 DAS)
.
.
.
12.5
18.8
16.3
41.0
58.8
45.0
51.0
66.3
53.8
3.5
4.0
3.3
4.0
4.8
3.8
3.0
4.3
3.5
Revolver @ 0.4 oz/M (28 DAS)
Revolver @ 0.8 oz/M (28 DAS)
Revolver @ 1.2 oz/M (28 DAS)
.
.
.
.
.
.
.
.
.
58.8
52.0
58.8
.
.
.
.
.
.
4.0
3.5
3.8
10.3
4.5
2.2
22.2
11.7
6.7
49.8
35.0
11.6
53.8
46.7
17.0
3.7
2.5
1.1
4.2
3.0
1.7
3.5
2.8
1.5
Non-Treated Control
Test Mean
LSD
* seeding date: August 24, 2004.
% bermuda = (-100%) Values are the mean of 4 replications.
Vigor = 1-6. 1=none, 4= moderate, 6 = extreme. Values are the mean of 4 replcations.
Test mean = Mean of all treatments and control for each date.
LSD Value = Least significant difference value, as treatment mean separation statistic.
Table 2 . Percent Bermudagrass cover and seedling Vigor as affected by 'Revolver' applied AT SEEDING.
University of Arizona, Karsten Turfgrass Research Facility. Tucson, AZ.
Treatment
7-Sep
%-berm
14-Sep
21-Sep
29-Sep
14-Sep
vigor
21-Sep
29-Sep
Revolver @ 0.4 oz/M (AT SEEDING)
Revolver @ 0.8 oz/M (AT SEEDING)
Revolver @ 1.2 oz/M (AT SEEDING)
6.3
5.5
4.0
13.3
10.0
7.0
34.3
29.3
25.5
44.3
38.3
34.3
2.5
1.8
2.0
2.5
2.8
2.8
2.0
2.0
2.0
Non-Treated Control
Test Mean
LSD
10.3
6.5
2.7
22.2
13.1
6.1
49.8
34.7
7.9
53.8
42.6
14.5
3.7
2.5
0.9
4.2
3.0
ns
3.5
2.4
ns
* seeding date: August 24, 2004.
% bermuda = (-100%) Values are the mean of 4 replications.
Vigor = 1-6. 1=none, 4= moderate, 6 = extreme. Values are the mean of 4 replcations.
Test mean = Mean of all treatments and control for each date.
LSD Value = Least significant difference value, as treatment mean separation statistic.
Table 3. Percent Bermudagrass cover and seedling Vigor as affected by 'Revolver' applied 7 days after seeding.
University of Arizona, Karsten Turfgrass Research Facility. Tucson, AZ.
Treatment
7-Sep
%-berm
14-Sep
21-Sep
29-Sep
14-Sep
vigor
21-Sep
29-Sep
Revolver @ 0.4 oz/M (7 DAS)
Revolver @ 0.8 oz/M (7 DAS)
Revolver @ 1.2 oz/M (7 DAS)
2.0
2.0
1.5
7.5
5.0
4.5
28.0
20.8
18.0
35.0
33.5
27.5
2.0
1.3
1.3
2.3
1.5
2.0
1.8
1.5
1.0
Non-Treated Control
Test Mean
LSD
10.3
3.9
1.7
22.2
9.8
6.7
49.8
29.1
11.6
53.8
37.4
13.3
3.7
2.0
0.9
4.2
2.5
1.6
3.5
1.9
1.3
* seeding date: August 24, 2004.
% bermuda = (-100%) Values are the mean of 4 replications.
Vigor = 1-6. 1=none, 4= moderate, 6 = extreme. Values are the mean of 4 replcations.
Test mean = Mean of all treatments and control for each date.
LSD Value = Least significant difference value, as treatment mean separation statistic.
Table 4. Percent Bermudagrass cover and seedling Vigor as affected by 'Revolver' applied 14 days after seeding.
University of Arizona, Karsten Turfgrass Research Facility. Tucson, AZ.
Treatment
Revolver @ 0.4 oz/M (14 DAS)
Revolver @ 0.8 oz/M (14 DAS)
Revolver @ 1.2 oz/M (14 DAS)
Non-Treated Control
Test Mean
LSD
7-Sep
%-berm
14-Sep
21-Sep
29-Sep
14-Sep
vigor
21-Sep
29-Sep
-
12.5
18.8
16.3
41.0
58.8
45.0
51.0
66.3
53.8
3.5
4.0
3.3
4.0
4.8
3.8
3.0
4.3
3.5
10.3
10.3
-
22.2
17.4
ns
49.8
48.6
12.7
53.8
56.2
ns
3.7
3.6
ns
4.2
4.2
ns
3.5
3.6
ns
* seeding date: August 24, 2004.
% bermuda = (-100%) Values are the mean of 4 replications.
Vigor = 1-6. 1=none, 4= moderate, 6 = extreme. Values are the mean of 4 replcations.
Test mean = Mean of all treatments and control for each date.
LSD Value = Least significant difference value, as treatment mean separation statistic.
Table 5. Percent Bermudagrass cover and seedling Vigor as affected by 'Revolver' applied 28 days after seeding.
University of Arizona, Karsten Turfgrass Research Facility. Tucson, AZ.
Treatment
Revolver @ 0.4 oz/M (28 DAS)
Revolver @ 0.8 oz/M (28 DAS)
Revolver @ 1.2 oz/M (28 DAS)
Non-Treated Control
Test Mean
LSD
7-Sep
%-berm
14-Sep
21-Sep
29-Sep
14-Sep
vigor
21-Sep
29-Sep
-
-
-
58.8
52.0
58.8
-
-
4.0
3.5
3.8
10.3
10.3
-
22.2
22.2
-
49.8
49.8
-
53.8
55.8
ns
3.7
3.7
-
4.2
4.2
-
3.5
3.7
ns
* seeding date: August 24, 2004.
% bermuda = (-100%) Values are the mean of 4 replications.
Vigor = 1-6. 1=none, 4= moderate, 6 = extreme. Values are the mean of 4 replcations.
Test mean = Mean of all treatments and control for each date.
LSD Value = Least significant difference value, as treatment mean separation statistic.
Table 6. Percent Bermudagrass cover and seedling Vigor as affected by 'Revolver' applied at 0.4 oz./M.
University of Arizona, Karsten Turfgrass Research Facility. Tucson, AZ.
Application Date
24-Aug (seeding date)
31-Aug (7 DAS)
7-Sep (14 DAS)
21-Sep (28 DAS)
Test Mean
LSD
7-Sep
6.3
2.0
4.1
ns
%-berm
14-Sep
21-Sep
13.3
34.3
7.5
28.0
12.5
41.0
11.1
ns
34.4
ns
29-Sep
44.3
35.0
51.0
58.8
14-Sep
2.5
2.0
3.5
-
vigor
21-Sep
2.5
2.3
4.0
-
29-Sep
2.0
1.8
3.0
4.0
47.3
19.4
2.7
ns
2.9
ns
2.7
1.5
* seeding date: August 24, 2004.
% bermuda = (-100%) Values are the mean of 4 replications.
Vigor = 1-6. 1=none, 4= moderate, 6 = extreme. Values are the mean of 4 replcations.
Test mean = Mean of all treatments and control for each date.
LSD Value = Least significant difference value, as treatment mean separation statistic.
Table 7. Percent Bermudagrass cover and seedling Vigor as affected by 'Revolver' applied at 0.8 oz./M.
University of Arizona, Karsten Turfgrass Research Facility. Tucson, AZ.
Application Date
24-Aug (seeding date)
31-Aug (7 DAS)
7-Sep (14 DAS)
21-Sep (28 DAS)
Test Mean
LSD
7-Sep
5.5
2.0
-
3.8
3.0
%-berm
14-Sep
21-Sep
10.0
29.3
5.0
20.8
18.8
58.8
-
11.3
5.1
36.3
11.5
29-Sep
38.3
33.5
66.3
52.0
14-Sep
1.8
1.3
4.0
-
vigor
21-Sep
2.8
1.5
4.8
-
29-Sep
2.0
1.5
4.3
3.5
47.5
19.4
2.3
0.6
3.0
1.1
2.8
2.0
* seeding date: August 24, 2004.
% bermuda = (-100%) Values are the mean of 4 replications.
Vigor = 1-6. 1=none, 4= moderate, 6 = extreme. Values are the mean of 4 replcations.
Test mean = Mean of all treatments and control for each date.
LSD Value = Least significant difference value, as treatment mean separation statistic.