Super Science TABLE 1 Plant growth regulator (PGR) rates, surfactant rates, surfactant classification and immediate action after application PGR Primo MAXX a PGR rate fl oz 1000 ft −2 0.25 0.25 0.25 0.25 0.25 Surfactant None Straight block co-polymer c Revolution d Organosilicone e Proprietary NIS None Straight block co-polymer Revolution Organosilicone Proprietary NIS f Surfactant rate NAb 8 fl oz 1,000 ft -2 8 fl oz 1,000 ft -2 0.5% v/v 0.5% v/v NA 8 fl oz 1,000 ft -2 8 fl oz 1,000 ft -2 Surfactant classification NA Wetting agent Wetting agent Adjuvant Adjuvant NA Wetting agent Wetting agent Adjuvant Adjuvant Immediate action after application Dry Dry Dry Dry Dry 0.5 in; watered in 0.5 in; watered in 0.5 in; watered in 0.5 in; watered in 0.5 in; watered in Cutless MEC g 0.56 0.56 0.56 0.56 0.56 0.5 percent v/v 0.5 v/v a Syngenta Co.; 11.3 percent a.i. b NA, not applicable. c Straight block co-polymer (Tria Global Solutions). d Modified methyl capped co-polymer (Aquatrols). e Exacto 524 (Exacto). f NIS, nonionic surfactant (Exacto 1057 [Exacto]). g SePRO Co., 16 percent a.i. TABLE 2 Application dates and final clipping collection dates for 2017 and 2018. The second application of the year occurred after a minimum of 1,000 growing degree days (GDD; base 0°C) was surpassed from the first application. Date applied Final clipping collection date Accumulated GDD a GDD 19 June 2017 31 Aug. 2017 9 July 2018 10 July 2018 a Continued from page 41 8 Aug. 2017 26 Oct. 2017 29 Aug. 2018 26 Oct. 2018 1,229 1,037 1,465 672 GDD is the summation of daily average air temperature in °C. TABLE 3 Application dates and final clipping collection dates for 2017 and 2018. The second application of the year occurred after a minimum of 1,000 growing degree days (GDD; base 0°C) was surpassed from the first application. Treatment Period — GDD a — PM b Time to maximum suppression — GDD — 341.9 328.0 364.0 349.4 359.0 Clipping yield suppressed — % — 42 63 46 52 46 1,620.6 c AB 1,581.4 AB 1,708.0 A 1,664.6 B 1,755.0 A PM + Straight Block Co-polymer d PM + Revolution e PM +Organosilicone f PM + Proprietary NIS g a GDD is the summation of daily average air temperature in degrees Celsius. b Syngenta Co., 11.3 percent a.i. c Different capital letters within a column indicate significant differences. d Tria Global Solutions, LLC. e Modified methyl capped co-polymer, Aquatrols f GExacto 524, Exacto g NIS, nonionic surfactant (Exacto 1057, Exacto) block co-polymer + PM suppressed yield by 63 percent, whereas the PM applied alone suppressed yield by only 42 percent. Organosilicone + PM suppressed clipping yield by 52 percent. Past research indicated the appli-cation r at e influe nc e s the amount of suppression but not the duration of clipping yield suppression (5). Organosilicone adjuvants could increase PM absorption and suppress clipping yield (3). The increased clipping yield suppression with these surfactants without increased suppression duration could suggest that the straight block co-polymer and organosilicone surfac-tants increased PM uptake. The proprietary nonionic surfactant (NIS) + CM reduced suppression compared to CM applied alone (Figure 1). The NIS + CM treatment had a maximum clipping yield suppression of 38 percent (Figure 1). The CM control had 49 percent suppression. We saw no significant differences in growth suppression duration between the CM treatments (data not shown). Mixing a surfactant with CM may have limited effects because CM is root-absorbed. The overall visual quality ratings Golfdom.com 42 // Golfdom June 2022
Golfdom June 2022: Page-42
