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 as a root drench to containerized Fraser fir [Abies fraseri (Pursh) Poir.] at various times of the year. Leader length, stem diameter, length of laterals, and number of subterminal buds were reduced the following growing season. Treatment during the 1994 growing season reduced lateral 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 caused needle discoloration and abscission at concentrations ≥4 mg·L-1. Leader growth was reduced more than branch elongation, which tended to make plants more decurrent. The utility of uniconazole in production of tabletop Fraser fir Christmas trees was unclear; reduced shoot elongation was often accompanied by fewer lateral buds and needle discoloration and/or abscission. Chemical name used: E-1-(p-Chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazole-1-penten-3-ol) (uniconazole).