Last updated 7/4/01 |
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Clark Throssell and Dan Weisenberger
Our objective was to determine if Confront on fertilizer was less injurious than Confront liquid spray applied to creeping bentgrass fairway turf.
Broadleaf weeds are a problem on bentgrass fairways. It is important to examine new formulations for safety to fairway bentgrass.
A stand of creeping bentgrass turf at the William H. Daniel Turfgrass Research and Diagnostic Center was selected as the site for this experiment. The turf was mowed at 0.5 inches three times a week with the clippings returned. Fertilizer was applied at the rate of 3.5 lbs N/1000 ft2 using a fairway grade complete fertilizer. The turf was irrigated to prevent any signs of stress. Fungicides were applied as needed to prevent damage.
Injury to the creeping bentgrass fairway turf was rated on 26 May (3 days after application), 30 May, 1 week after treatment (1 WAT), 10 June (2 WAT), 15 June (3 WAT) and 22 June (4 WAT). Turf injury was nonexistant or the turf injury rating was less than 1.0 for most treatments on nearly all rating dates (Table 1). Only Confront 3SL and 0.75 lbs ae/A on 26 May and 30 June and Confront 3SL at 0.375 lbs ae/A on 30 May caused significantly more turf injury to treated plots than was observed on the untreated check. The duration of the turf injury was fairly short. By 10 June (2 WAT) no turf injury was observed on any plot.
It appears that the granular formulations of Confront and the liquid formulation of Lontrel cause less turf injury to fairway creeping bentgrass turf than liquid applications of Confront.
Table 1. Turf injury to fairway creeping bentgrass caused by application of Confront and Lontrel. |
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| Rate of | 26 | 30 | 10 | 15 | 22 | |
| Treatment | application | May | May | June | June | June |
| lbs a.e./A | ||||||
| Confront 0.48 AE G | 0.65 | 0.5a | 0.0 | 0.0 | 0.0 | 0.0 |
| Confront 0.48 AE G | 0.75 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Confront 0.48 AE G | 1.3 | 0.3 | 0.3 | 0.0 | 0.0 | 0.0 |
| Confront 3SL | 0.375 | 0.0 | 1.5 | 0.0 | 0.0 | 0.0 |
| Confront 3SL | 0.75 | 2.0 | 4.0 | 0.0 | 0.0 | 0.0 |
| Lontrel 3SL | 0.25 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Check | --- | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| . | ||||||
| LSD (0.05) | 1.1 | 0.4 | NS | NS | NS | |
| a Turf injury was rated on a scale of 0 to 10 where 0 = no injury and 10 = brown turf. | ||||||
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