The Chemical Growth Regulation of Bulb Crops Using Flurprimidol as Foliar Sprays, Substrate Drenches, and Pre-Plant Bulb Soaks

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Title: The Chemical Growth Regulation of Bulb Crops Using Flurprimidol as Foliar Sprays, Substrate Drenches, and Pre-Plant Bulb Soaks
Author: Krug, Brian Alan
Advisors: Dr. John M. Dole, Committee Member
Dr. Judith Thomas, Committee Member
Dr. Brian E. Whipker, Committee Chair
Abstract: When producing bulb crops, height control is often required to obtain plants which are proportional to pot size, meet shipping requirements, and reduce postharvest stem stretch. An effective means of controlling plant height is the use of plant growth regulators (PGRs). A number of PGRs are commonly used for bulb crops in the floriculture industry today including: ancymidol, ethephon, paclobutrazol, and uniconazole. Flurprimidol, currently available in Europe as a 1.5% formulation, will soon be released in the United States as a 0.38% formulation under the trade name Topflor. Experiments were conducted to determine how the efficacy of flurprimidol compared to currently used PGRs on caladium, hyacinth, lily, narcissus, and tulip crops when applied as a foliar spray, substrate drench, or pre-plant bulb soak. Additionally, production practices for the use of flurprimidol pre-plant soaks with hyacinths were explored to determine advance soak timing, soak duration, efficacy over repeated use, and disposal of soak solution. Foliar sprays of flurprimidol were only trialed on tulips and 'Star Gazer' lily. Concentrations > 80 mg.L-1 were required for both crops to control stem stretch. Flurprimidol substrate drenches at 0.5 mg active ingredient (a.i.) controlled plant height on tulip and 'Star Gazer' lily. Stem stretch was controlled on hyacinth with 1 mg a.i flurprimidol was required and 2 mg a.i. flurprimidol for 'Red Flash' caladium. To control stem stretch on 'Tete a Tete' narcissus 0.69 mg a.i. was required, substrate drenches were not trialed on 'Dutch Master' Flurprimidol applied as a pre-plant soak controlled plant height on hyacinth and tulips at concentrations ranging from 10 to 25 mg.L-1, depending on cultivar. Narcissus plant height was controlled with flurprimidol pre-plant bulb soaks at 30 and 20 mg.L-1 for cultivars 'Tete a Tete' and 'Dutch Master', respectively. 'Star Gazer' lily height was controlled with a 25 mg.L-1 flurprimidol pre-plant bulb soak while 'Red Flash' caladiums were not effected at concentrations < 40 mg.L-1.
Date: 2004-12-01
Degree: MS
Discipline: Horticultural Science
URI: http://www.lib.ncsu.edu/resolver/1840.16/1347


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