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Abstract
Foliar application of 0.1 to 1% dikegulac-sodium [sodium 2,3:4,6-di-0-isopropyl-idene-2-keto-L-gulonate (Atrinal)] inhibited (shoot) elongation and axillary bud break for more than 3 months in field grown Xylosma congestum, (Lour.) Merr., Pyracantha coccinea (Roem.), Callistemon citrinus (Curt.), Cotoneaster pannosa (Franch.), and Nerium oleander L. Phytotoxic symptoms were minor in most species, but Nerium, chlorosis of young leaves and necrotic areas on tips of half expanded leaves were noted. Applications made immediately after pruning eliminated this problem. Fully expanded leaves were undamaged and their viability more than 5 months after treatment with 1% solutions were equal to that of control plants. Greenhouse trials with Eucalyptus globulus Labill., Fraxinus uhdei (Wenz.) lingelsh, and Ulmus parvifolia Jacq. indicated that this compound will also be a useful inhibitor for landscape tree species, although at 0.4%, phytotoxicity in Eucalyptus may be too severe for general application.
Abstract
A new formulation of maleic hydrazide (Royal Slo-Gro), containing the surfactant polyoxyethylene trimethylnonyl ether (TMN-10), was superior to the maleic hydrazide formulation, containing polyoxyethylene nonyl surfactant (X-77) for inhibiting shoot elongation of Pinus radiata L., Xylosma congestum (Lour.) Merr., Viburnum japonicum (Thunb.) Spreng., and Coprosma repens A. Rich. The X-77 formulation was superior to the one containing TMN-10 for inhibiting growth of Juniperus sabina L. ‘Tamariscifolia’, Pyracantha coccinea (Roem.), and Callistemon citrinus (Curt.). There was little difference between the two formulations in tests with Cotoneaster pannosa (Franch.) and mixed results were obtained with Nerium oleander L. The greatest advantage of the TMN-10 formulation was manifested in Pinus where inhibition occurred without severe foliar discoloration, necrosis, or tip dieback which are characteristic of other maleic hydrazide formulations.
Abstract
N-pyrrolidino succinamic acid (Uni-F529) was considerably superior to succinic acid 2,2 dimethyl hydrazide (daminozide, SADH) in inhibiting stem elongation in Phaseolus vulgaris F. ‘Black Valentine’ and Chrysanthemum morifolium Ramat. ‘Bright Golden Anne’. This was true in winter or summer greenhouses. Under controlled temperature and light conditions tissue concentrations of daminozide were higher than those for Uni-F529. Neither daminozide nor Uni-F529 was metabolized significantly in beans during the 3 to 7 day test periods. The greater activity of the pyrrolidino analog relative to daminozide must reflect increased activity at the site of action and/or reduced storage of Uni-F529 at inactive sites in plants.