Effect of Pruning on the Growth Inhibiting Activity of Sumagic (Uniconazole)

Abstract Pruning date was investigated as a possible factor influencing the inhibitory activity of Sumagic (uniconazole) on growth of 6 container grown woody landscape plants. Plants were pruned 1 or 10 days before uniconazole was applied as a foliar spray or medium drench on June 22, 1988. Plant height and width were recorded weekly through November 30, 1988. Pruning date influenced the pattern of growth and/or the final size of plants treated with foliar-applied uniconazole. It also influenced uniconazole's inhibitory activity the first 2 to 3 weeks after application. Uniconazole was most effective on Pyracantha and Ligustrum lucidum the first 2 to 3 weeks after treatment if applied 1 day after pruning. Drench applications resulted in greater growth inhibition than foliar sprays; however, drench treatments caused unacceptable reduction in plant size.