Effect of nine growth retardants applied to loblolly and slash pine

Abstract

In an effort to dwarf seed orchard trees without reducing fruitfulness, nine growth-retardant chemicals were applied at several concentrations each as either aqueous foliar sprays or oil-based bark bands. All treatments which significantly retarded growth also caused injury or death. Mefluidide, as a 0.7% foliage spray, reduced growth and caused only minimal injury. Effects of the chemicals on seed production could not be observed, as no control or treated trees flowered. Slash pine was more sensitive to the chemicals than loblolly pine.

Controlling Growth of Tabletop Christmas Trees with Plant Growth Retardants

“…Considerable research has been performed on PGRs to determine their effectiveness in controlling growth of conifer species (Asher, 1963;Dunberg and Eliasson, 1972;Groninger and Seiler, 1997;Hare, 1982;Keever and West, 1992;Kuo and Pharis, 1975;Ruddat and Pharis, 1966;Ruter, 1994;Van den Driessche, 1989, 1996Weston et al, 1980). In general, the emphasis of these studies has been to determine the effectiveness of PGRs to reduce transplanting stress or as a means of height control under utility rights-of-way.…”

Naphthaleneacetic Acid Reduces Leader Growth of Fraser Fir Christmas Trees

“…Ethylene is a naturally produced hormone that causes inactivation of auxins, leaf abscission, and growth inhibition (Kefeli and Kalevitch, 2003). At high levels, NAA can reduce growth and cause injury or death to plants (Boswell et al, 1976;Domir and Wuertz, 1982;Hare, 1982;Kramer and Kozlowski, 1979;Wilson, 1983). Therefore, objectives of this research were to 1) determine the effect of SS-RTU on leader growth of fraser fir; and 2) compare two methods of application.…”

Response of Established Landscape Plants to Uniconazole

“…The electric utility industry spends an estimated $800 million per year for tree trimming under power lines (Watson, 1987), while hundreds of millions of dollars are spent maintaining landscape trees and shrubs. Numerous plant growth regulators (PGRs) have been evaluated for retardation of woody plant growth, but most remain uneconomical or cause undesirable side effects (Hare, 1982;Weston et al, 1980). Several PGRs, including dikegulac sodium (Atrimmec, Hoffman-La-Roche, Nutley, N.J.), maleic hydrazide (Royal Slo-Gro, Uniroyal, Bethany, Conn.), mefluidide (Embark, PBI/Gordon, Kansas City, MO.…”

“…The container-grown woody plants evaluated in the cited references were all angiosperms. Growth retardants generally have been less effective, non-effective, or phytotoxic to gymnosperms (Hare, 1982;Weston et al, 1980). We performed this research to determine the influence of soil-and foliar-applied uniconazole on two established, field-grown woody landscape species under simulated lowmaintenance landscape conditions.…”

“…Numerous growth retardants have been tested on selected conifer species. Many of these chemi-cals were phytotoxic, caused abnormal growth of seedlings and older trees, or did not reduce the plant's growth rate (Hare, 1982;Weston et al, 1980). Triazole retardants are potent growth regulators of a broad range of angiosperms, including monocotyledons and dicotyledons (Keever et al, 1990;Warren, 1990).…”