EFFECT OF UNICONAZOLE ON SHOOT GROWTH AND BUDSET OF CONTAINERIZED FRASER FIR

In two experiments, uniconazole (0.25 to 16 mg.L-1 a.i.) was applied a s a root drench to containerized Fraser fir [Abies fraseri (Pursh) Poi r.] at various times of the year. Leader length, stem diameter, length of laterals, and number of subterminal buds were reduced the followin g growing season. Treatment during the 1994 growing season reduced lat eral bud formation on the leader in 1995, whereas treatment with 8 or 16 mg.L-1 in Mar. 1995 (prior to budbreak) increased it. Uniconazole c aused needle discoloration and abscission at concentrations greater th an or equal to 4 mg.L-1. Leader growth was reduced more than branch el ongation, which tended to make plants more decurrent. The utility of u niconazole in production of tabletop Fraser fir Christmas trees was un clear; reduced shoot elongation was often accompanied by fewer lateral buds and needle discoloration and/or abscission. Chemical name used: nyl)-4,4-dimethyl-2-(1,2,4-triazole-1-penten-3-ol) (uniconazole).