paclobutrazol or uniconazole at a concentration of 5 mg·L −1 on de-eyed tubers were shown to retard overall foliage height ( Wilfret, 1993 ). Flurprimidol (Topflor; SePRO Corp., Carmel, Ind.) has been available in Europe for more than 20 years as a 1
Brian A. Krug, Brian E. Whipker, and Ingram McCall
Christopher J. Currey, Roberto G. Lopez, Brian A. Krug, Ingram McCall, and Brian E. Whipker
; Sanderson et al., 1975 ; Wilfret, 1987 ; Wilfret and Reiser, 1996 ). Flurprimidol (Topflor; SePRO Corp., Carmel, IN) is available in the U.S. market as a 0.38% liquid formulation. In addition to ancymidol, paclobutrazol, and uniconazole, flurprimidol
Jared Barnes, Brian Whipker, Wayne Buhler, and Ingram McCall
methods Expt. 1. ‘Orange Tiger’ tiger lily bulbs (16- to 18-cm circumference; Berbee Bulb Co., Marysville, OH) were treated with flurprimidol (Topflor; SePRO Corp., Carmel, IN) on 13 Feb. 2009; bulbs were hydrated in 17 °C water for 1 h, allowed to drain 1
William B. Miller
product, Topflor (SePRO, Carmel, IN) and used to dip 144 narcissus and 120 hyacinth bulbs (10 min dips) and then held in darkness at 17 °C. Three weeks later, an identical solution was prepared and used to dip a second group of bulbs and then also held in
James L. Gibson and Shannon Crowley
The objective of this study was to compare the effects of flurprimidol or paclobutrazol on the growth of four bedding plant species: nicotiana (Nicotiana ×sanderae), portulaca (Portulaca grandiflora), verbena (Verbena ×hybrida), and zinnia (Zinnia elegans). Plants were treated 10 days after transplanting with foliar sprays of five concentrations (in mg·L–1): 5, 10, 20, 40, or 80 from each plant growth regulator. Phytotoxicity symptoms were not observed on plants sprayed with flurprimidol or paclobutrazol. Foliar sprays of flurprimidol at 20 mg·L–1 and paclobutrazol at 80 mg·L–1 provided sufficient growth control of nicotiana for retail sales, while concentrations of 40 to 80 mg·L–1 flurprimidol produced more compact plants for wholesale production. For portulaca only flurprimidol sprays of 40 and 80 mg·L–1 produced plants that were proportionate to the container. Foliar sprays of flurprimidol at 20 mg·L–1 and paclobutrazol at 40 mg·L–1 controlled growth of verbena and zinnia suitable for retail sales, while concentrations of 40 mg·L–1 flurprimidol and 80 mg·L–1 paclobutrazol provided more compact plants which may be useful for wholesale growers. Concentrations were based under Florida conditions and should be adjusted for other areas.
Christopher J. Currey and Roberto G. Lopez
0, 0.05, 0.10, 0.15, 0.20, or 0.25 mg·L −1 flurprimidol (Topflor; SePRO, Carmel, IN) was applied to substrate surfaces 14 d after pinching when shoots were ≈1 inch long. Plants were irrigated as necessary with acidified water supplemented with water
Alicain S. Carlson, John M. Dole, and Brian E. Whipker
greenhouse at night/day set points of 60/75 °F starting 9 May 2012. On 25 June 2012, when the emerging leaf whorl was ≈5-cm tall, each pot was drenched with 4 fl oz of flurprimidol (Topflor; SePRO Corp., Carmel, IN), uniconazole (Sumagic; Valent USA
Brian E. Whipker, Ingram McCall, and Brian A. Krug
Flurprimidol was applied as a foliar spray (12.5, 25.0, 37.5, 50.0, or 62.5 mg·L-1) or as a substrate drench (0.015, 0.03, 0.06, 0.12, or 0.24 mg/pot a.i.) to determine its efficacy on `Blue Champion' exacum (Exacum affine). Flurprimidol substrate drenches were more consistent in controlling plant growth than foliar sprays. Substrate drenches of 0.03 mg/pot a.i. or foliar sprays ≥50 mg·L-1 resulted in smaller plant heights and diameters than the untreated control. With the use of flurprimidol, exacum growers have another plant growth regulator (PGR) available to control excessive growth.
Brian A. Krug, Brian E. Whipker, Ingram McCall, and John M. Dole
Preplant bulb soaks of flurprimidol, paclobutrazol, and uniconazole; foliar sprays of ethephon and flurprimidol; and substrate drenches of flurprimidol were compared for height control of `Anna Marie' hyacinths (Hyacinthus orientalis). Preplant bulb soak concentrations of flurprimidol and paclobutrazol were from 25 to 400 mg·L-1, and uniconazole from 5 to 80 mg·L-1. Height control was evaluated at anthesis and 11 days later under postharvest conditions. Ethephon (250 to 2000 mg·L-1) and flurprimidol (5 to 80 mg·L-1) foliar sprays were ineffective. Flurprimidol (0.25 to 4 mg/pot) drenches had no effect during forcing, but controlled postharvest height at concentrations ≥0.25 mg/pot a.i. with at least 4% shorter plants than the untreated control. Preplant bulb soaks resulted in height control with flurprimidol ≥25 mg·L-1, paclobutrazol ≥100 mg·L-1, and uniconazole ≥40 mg·L-1; having at least 9%, 6%, and 19%, respectively, shorter plants than the untreated control. Based on our results, flurprimidol preplant bulb soaks have a greater efficacy than either uniconazole or paclobutrazol. Preplant PGR soaks are a cost-effective method of controlling plant height of hyacinths because of the limited amount of chemical required to treat a large quantity of bulbs.
Brian A. Krug, Brian E. Whipker, Ingram McCall, and John M. Dole
Preplant bulb soaks of ancymidol, flurprimidol, paclobutrazol, and uniconazole; foliar sprays of flurprimidol; and substrate drenches of flurprimidol, paclobutrazol, and uniconazole were compared for height control of `Prominence' tulips (Tulipa sp.). Height control was evaluated at anthesis in the greenhouse and 10 days later under postharvest conditions. Substrate drenches of ancymidol, flurprimidol, and paclobutrazol resulted in adequate control using concentrations of 0.5, 0.5, and 1 mg/pot a.i. (28,350 mg = 1 oz), respectively. At these concentrations, ancymidol drenches cost $0.06/pot and paclobutrazol drenches $0.03/pot. Since flurprimidol is not yet available and no price is available, growers will need to assess the cost compared to ancymidol and paclobutrazol. Flurprimidol foliar sprays at <80 mg·L–1 (ppm) were ineffective in controlling height during greenhouse forcing, but during postharvest evaluation 80 mg·L–1 resulted in 14% shorter plants than the untreated control. Preplant bulb soaks of flurprimidol, paclobutrazol, and uniconazole at concentrations of 25, 50, and 10 mg·L–1, respectively, effectively controlled plant height. Preplant plant growth regulator soaks are a cost-effective method of controlling plant height of tulips because of the limited amount of chemical required to treat a large quantity of bulbs.