1998 Iowa Turfgrass Research Report
Effect of Beacon on Kentucky Bluegrass Cultivars
Barbara R. Bingaman, Nick E. Christians, & Michael B. Faust
The objective of this study was to evaluate CGA #136872 (Beacon) for phytotoxicity on four Kentucky bluegrass cultivars. This study was conducted at the ISU Horticulture Research Station north of Ames, IA. Identical studies were conducted in four Kentucky bluegrass cultivars: 'common', 'Glade', 'Park', and 'Ram I'. The soil in all four plots was a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll). The 'common' plot had 3.65% organic matter, a pH of 5.42, 3 ppm P, and 93 ppm K and the 'Glade' plot had 4.0% organic matter, a pH of 6.85, 5 ppm P, and 76 ppm K. The 'Park' plot had 3.6% organic matter, a pH of 7.03, 17 ppm P, and 93 ppm K and the 'Ram I' plot had 3.9% organic matter, a pH of 7.00, 3 ppm P, and 76 ppm K.
Rainfall was sporadic during the study. Supplemental irrigation was used in all plots except the 'common' plot to keep the bluegrass in good growing condition.
These studies were designed as randomized complete blocks with three replications. There were four treatments including an untreated control. Novartis CGA #136872 (Beacon) was applied in single applications at 20 g and 40 g product/A. CGA #136872 (Beacon) also was applied in split applications at 10 g product/A. A methylated seed oil, SCOIL MSO, was added to all treatments at 0.25% V/V except the untreated control (Table 2). The treatments were applied at 30 psi using a CO2 backpack sprayer equipped with TeeJet #8006 flat fan nozzles. Initial treatments were made on July 11. Sequential treatments were applied on July 24, 1997.
Phytotoxicity and visual quality data were taken weekly from July 15, 1997 through September 18. Phytotoxicity was assessed using a 9 to 1 scale: 9 = no damage, 7 = slight chlorosis, 5 = serious chlorosis, and 1 = dead turf (Tables 1-4). Visual quality was assessed using a 9 to 1 scale: 9 = best, 6 = lowest acceptable, and 1 = worst quality (Tables 5-8). Data were analyzed with the Statistical Analysis System (SAS, version 6.10) and the Analysis of Variance (ANOVA) procedure. Means were compared using Fisher's Least Significant Difference (LSD) test. No phytotoxicity was detected on the 'common' bluegrass following the initial and sequential applications (Table 1). There was a slight chlorosis on 'Glade' bluegrass on July 30 following the sequential treatment of CGA #136872 (Beacon) at 10 g product/A on July 24 (Table 2). This discoloration was gone by August 6. On July 24, there was a general slight chlorosis on all treated 'Park' bluegrass (Table 3). By July 30, the quality of the treated 'Park' was the same as the untreated. The 'Ram I' bluegrass that received a sequential treatment on July 24 showed a moderate chlorotic effect on July 30. Bluegrass treated with an initial application of CGA #136872 (Beacon) at 40 g product/A had a slight chlorosis on this same date. By August 6, these symptoms were no longer present.
Turf quality was the same for treated and untreated 'common' bluegrass (Table 5). Because this plot was not irrigated, the sporadic rainfall can probably explain the poor quality in this plot during the summer. Turf quality of 'Glade' treated with CGA #136872 (Beacon) at 10 g product/A in split applications was lower than the other treated and untreated bluegrass on July 30 as a result of the sequential application on July 24 (Table 6). This difference was not evident on August 6. On July 24, 'Park' bluegrass treated with CGA #136872 (Beacon) had poorer quality than the untreated turf (Table 7). Turf quality was the same for treated and untreated 'Park' by July 30 and no other quality differences were noted throughout the season. Treatment with CGA #136872 (Beacon) resulted in lower turf quality of 'Ram I' bluegrass on July 24 (Table 8). On July 30, there also was a further quality decrease in 'Ram I' bluegrass that received a sequential treatment of CGA #136872 (Beacon) on July 24. The quality differences among the treated and untreated plots had disappeared by August 6.
In treated plots where decreases in quality occurred, they were not intensified by increases in the rate of CGA #136872 (Beacon). This would indicate that the phytotoxicity may have been due to the SCOIL rather than the CGA #136872 (Beacon). Future studies should include a SCOIL treatment with no CGA #136872 (Beacon) included.
Table 1. Phytotoxicity1 of 'Common' Kentucky bluegrass treated in the 1997 Cultivar Phytotoxicity Study.
|
|
Material |
Rate product/A. |
Number of appl |
July 15 |
July 24 |
July 30 |
Aug 6 |
Aug 15 |
Aug 21 |
Aug 28 |
Sept 5 |
Sept 11 |
Sept 18 |
|
1 |
Untreated Control |
NA |
1 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
|
2 |
CGA #136872 (Beacon) + SCOIL MSO |
10.0 g + 0.25% V/V |
2 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
|
3 |
CGA #136872 (Beacon) + SCOIL MSO |
20.0 g + 0.25% V/V |
1 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
|
4 |
CGA #136872 (Beacon) + SCOIL MSO |
40.0 g + 0.25% V/V |
1 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
|
|
LSD0.05 |
|
|
NS |
NS |
NS |
NS |
NS |
NS |
NS |
NS |
NS |
NS |
Initial treatments were applied July 11 and sequentials were applied on July 24, 1997.
NS = means are not significantly different at the 0.05 level.
1Phytotoxicity was assessed using a 9 to 1 scale: 9 = no damage, 7 = slight chlorosis, 5 = severe chlorosis, and 1 = dead turf.
Table 2. Phytotoxicity1 of 'Glade' Kentucky bluegrass treated in the 1997 Cultivar Phytotoxicity Study.
|
|
Material |
Rate product/A. |
Number of appl |
July 15 |
July 24 |
July 30 |
Aug 6 |
Aug 15 |
Aug 21 |
Aug 28 |
Sept 5 |
Sept 11 |
Sept 18 |
|
1 |
Untreated Control |
NA |
1 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
|
2 |
CGA #136872 (Beacon) + SCOIL MSO |
10.0 g + 0.25% V/V |
2 |
9 |
9 |
7 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
|
3 |
CGA #136872 (Beacon) + SCOIL MSO |
20.0 g + 0.25% V/V |
1 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
|
4 |
CGA #136872 (Beacon) + SCOIL MSO |
40.0 g + 0.25% V/V |
1 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
|
|
LSD0.05 |
|
|
NS |
NS |
NS |
NS |
NS |
NS |
NS |
NS |
NS |
NS |
Initial treatments were applied July 11 and sequentials were applied on July 24, 1997.
NS = means are not significantly different at the 0.05 level.
1Phytotoxicity was assessed using a 9 to 1 scale: 9 = no damage, 7 = slight chlorosis, 5 = severe chlorosis, and 1 = dead turf.
Table 3. Phytotoxicity1 of 'Park' Kentucky bluegrass treated in the 1997 Cultivar Phytotoxicity Study.
|
|
Material |
Rate product/A. |
Number of appl |
July 15 |
July 24 |
July 30 |
Aug 6 |
Aug 15 |
Aug 21 |
Aug 28 |
Sept 5 |
Sept 11 |
Sept 18 |
|
1 |
Untreated Control |
NA |
1 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
|
2 |
CGA #136872 (Beacon) + SCOIL MSO |
10.0 g + 0.25% V/V |
2 |
9 |
7 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
|
3 |
CGA #136872 (Beacon) + SCOIL MSO |
20.0 g + 0.25% V/V |
1 |
9 |
7 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
|
4 |
CGA #136872 (Beacon) + SCOIL MSO |
40.0 g + 0.25% V/V |
1 |
9 |
7 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
9 |
|
|
LSD0.05 |
|
|
NS |
NS |
NS |
NS |
NS |
NS |
NS |
NS |
NS |
NS |
Initial treatments were applied July 11 and sequentials were applied on July 24, 1997.
NS = means are not significantly different at the 0.05 level.
1Phytotoxicity was assessed
using a 9 to 1 scale: 9 = no damage, 7 = slight chlorosis, 5
= severe chlorosis, and 1 = dead turf.
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ISU Horticulture:Publications:1998 Turfgrass Report | College of Agriculture |