Bradford C. Bearce and Suman Singha
Harry K. Tayama and Stephen A. Carver
Residual activity of a single uniconazole spray (15 mg a.i./liter), uniconazole drench (600 μg a.i./pot), and daminozide spray (5000 mg a.i./liter) were compared to an untreated control using the `Bright Golden Anne' chrysanthemum [Dendranthema grandiflorum (Ramat.) Kitamura]. Based on weekly internode growth, spray and drench treatments with daminozide and uniconazole remained active for 2 to 2.5 and 3 to 3.5 weeks, respectively. Chemical names used: butanedioic acid mono (2,2-dimethylhydrazide) (daminozide); (E)-1-(p-chlorophenyl)-4,4-diemethyl 1-2(1,2,4-triazol-2-yl)-l-penten-3-01 (uniconazole).
Terri Woods Starman, Teresa A. Cerny, and Tracy L. Grindstaff
Height control and flowering responses to uniconazole spray or drench treatments were measured for `Multibloom Scarlet' and `Red Elite' geranium (Pelargonium ×hortorum L.H. Bailey). Total plant height of both cultivars was reduced proportionately to the height of a 10-cm container when the uniconazole drench concentration was 0.025 mg a.i./pot. Used as a spray, uniconazole was not as effective in restricting total plant height of either cultivar. Foliage height was shortened more than inflorescence height. Inflorescence diameter was decreased with increasing uniconazole drench concentrations. Sprays did not affect inflorescence diameter of either cultivar. Uniconazole effect on days to flower varied with cultivar and application method. Chemical name used: (E)-(S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ene-3-ol (uniconazole).
Terri Woods Starman
This study investigated the effects of concentration and application time of uniconazole as a spray for single- or double-pinched ornamental pepper (Capsicum annuum L. `Holiday Cheer'). Concentrations from 5.0 to 15.0 mg·liter-1 gave adequate height control, except that 15.0 mg·liter-1 reduced height excessively when applied 8, but not 10, weeks after sowing. Increasing uniconazole concentration increased red fruit percentage when applied at 10, but not 8, weeks after sowing. These results indicate that the later application was beneficial and may lessen the overdosing problem associated with triazole growth regulators. Chemical name used: (E)-(S)-1-(4-chlrophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ene-3-oll(uniconazole).
Terri Woods Starman and P.T. Gibson
The effectiveness of uniconazole for height control of Hypoestes (Hypoestes phyllostachya Bak. `Pink Splash') was determined, and the persistence of uniconazole with chlormequat and daminozide for limiting stem elongation in a low-light interior environment was compared. Spray and drench applications of uniconazole decreased plant height linearly with increased concentration. Two uniconazole sprays at 5.0 mg·liter -1, 0.05 mg a.i./pot uniconazole drench, or two chlormequat sprays at 2500 mg·liter-1 resulted in equally aesthetic plant size for 0.4-liter pots. Chlormequat was more effective than uniconazole for reducing rate of growth in the postharvest environment. No difference in postproduction rate of growth occurred between two sprays at 5.0 mg·liter-1 and 0.05 or 0.10 mg a.i./pot drench treatments of uniconazole. Chemical names used: 2-chloro -N,N,N- trimethylethanaminium chloride (chlormequat chloride); butanedioic acid mono(2,2-dimethylhydrazide) (daminozide); (E)-(S) -1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-l1ene-3-ol (uniconazole).
Terri Woods Starman
Single and multiple sprays of uniconazole at 0, 5, 10, or 20 mg·liter-1 were compared with daminozide sprays at 2500 mg·liter-1 applied twice for height control of Dendranthema × grandiflorum (Ramat.) Kitamura (Chrysanthemum × morifolium Ramat.) `Puritan' and `Favor'. A single uniconazole spray at 20 mg·liter-1 applied 2 weeks after pinching or two uniconazole applications at 10 mg·liter-1 applied 2 and 4 weeks after pinching were as effective as daminozide for reducing height. Drenches of uniconazole at 0, 0.025, 0.05, or 0.10 mg a.i./pot were compared with ancymidol drenches at 0.45 mg a.i./pot for controlling height of `Bright Golden Anne'. Although ancymidol was more effective, a 0.10-mg uniconazole drench adequately reduced height.
Terri Woods Starman
One and two foliar spray and single-drench applications of uniconazole were applied to Eustoma grandiflorum (Raf.) Shinn (lisianthus) `Yodel Blue' to determine optimal concentrations for potted plant height control. A single uniconazole spray at 10.0 mg·liter-1 applied 2 weeks after pinching, two uniconazole applications at 5.0 mg·liter -1 applied 2 and 3 weeks after pinching, or a drench at 1.60 mg a.i. per pot applied 2 weeks after pinching gave equally good height control. At these concentrations, uniconazole was similar in its effect on plant height to daminozide foliar sprays at 7500 and 2500 mg·liter-l applied once and twice, respectively. Drenching with uniconazole at 1.60 mg a.i. per pot did not increase days to flower (DTF), whereas foliar spray applications did. Drenching did not reduce flower size, but increased flower number at time of harvest. Chemical names used: α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol); butanedioic acid mono(2,2-dimethylhydrazide) (daminozide);(E)-(S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ene-3-01 (uniconazole).
Harry K. Tayama and Stephen A. Carver
Uniconazole spray or drench applications to `Yours Truly' zonal geranium (Pelargonium × hortorum L.H. Bailey) and `Bright Golden Anne' and Yellow Favor' chrysanthemums [Dendranthema ×grandiflorum (Ramat.) Kitamura] were made to evaluate efficacy and identify optimum application concentrations. Spray applications at 10 mg a.i./liter retarded stem elongation in unpinched zonal geranium comparable to chlormequat at 1500 mg a.i./liter. `Bright Golden Anne' was more sensitive to uniconazole than `Yellow Favor'. Uniconazole spray concentrations of 20 to 30 mg a.i./liter retarded plant height equal to daminozide at 5000 mg a.i./liter. Chemical names used: 2-chloro-N,N,N-trimethylethanaminium chloride (chlormequat); butanedioic acid mono (2,2-dimethylhydrazide) (daminozide); (E)-(S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ene-3-ol (uniconazole).
Gary J. Keever and William J. Foster
`Redwings' and `Gloria' azaleas (Rhododendron × `Redwings' and `Gloria') were treated with foliar sprays of uniconazole, paclobutrazol, or daminozide to suppress bypass shoot development and promote flower initiation and development. Uniconazole at 5 and 25 mg·liter-1 suppressed bypass shoot development of `Redwings' and `Gloria', respectively. Flowering of `Gloria', but not `Redwings', was delayed slightly with uniconazole sprays up to 25 mg·liter-1 ; with the highest uniconazole concentration, 200 mg·liter-1, flowering was delayed as much as 18 days. Flower count of `Gloria' was not affected by lower concentrations of uniconazole, but it was greatly reduced in both cultivars with concentrations above 75 mg·liter-1. Uniconazole was more active than paclobutrazol sprays of similar concentrations or than two daminozide sprays of 3000 mg·liter–1 . Chemical names used: (E)-1-(p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol (uniconazole); (2RS,3RS)-1-(4-chlorophenyl)-2-(1,1-dimethylethyl)-(1H-1,2,4,-triazol-l-yl-)pentan-3-ol (paclobutrazol); butanedioic acid mono(2,2-dimethylhydrazide (daminozide),
Douglas A. Bailey and William B. Miller
Plants of Euphorbia pulcherrima Wind. `Glory' were grown under total irradiances of 13.4, 8.5, or 4.0 mol·m-2·day-1 and sprayed with water (control), 2500 mg daminozide/liter + 1500 mg chlormequat chloride/liter (D + C), 62.5 mg paclobutrazol/liter, or 4, 8, 12, or 16 mg uniconazole/liter to ascertain plant developmental and postproduction responses to treatment combinations. Anthesis was delayed for plants grown under the lowest irradiance. Anthesis was delayed by the D + C treatment, whereas other growth retardant treatments had no effect on anthesis date. Irradiance did not affect plant height at anthesis, but all growth retardant treatments decreased height over control plants. Inflorescence and bract canopy diameters were decreased at the lowest irradiance level. Growth retardants did not affect individual inflorescence diameters, but all, except paclobutrazol and 4 and 8 mg uniconazole/liter, reduced bract canopy diameter compared with control plants. Plants grown under the lowest irradiance developed fewer inflorescences per plant and fewer cyathia per inflorescence. Cyathia abscission during a 30-day postanthesis evaluation increased as irradiance was decreased; cyathia abscission was unaffected by growth retardant treatment. Leaf abscission after 30 days postanthesis was lowest for plants grown under the lowest irradiance. At 30 days postanthesis, all growth retardant treatments increased leaf abscission over controls. Results indicate that irradiance and growth retardant treatments during production can affect poinsettia crop timing, plant quality at maturity, and subsequent postproduction performance. Chemical names used: 2-chloroethyl-N,N,N-trimethylammonium chloride (chlormequat chloride); butanedioic acid mono (2,2-dimethyl hydrazide) (daminozide); β-[(4-chlorophenyl) methyl]- α -(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol), (E)-1-(p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-l-penten-3-ol (uniconazole, XE-1019).