| Summary: | To defoliate Ligustrum vulgare and Spiraea x arguta – ethephon, KJ, Mg(ClO3)2•6H2O, CuSO4•5H2O and (NH4)2SO4 in various concentrations were used alone or in mixtures. Treating plants with potassium iodide gave the best results. KJ concentrations of 0.05-0,1% and 0.1-0.% were sufficient to defoliate Spiraea and Ligusturm respectively. Magnesium chlorate at concentration of 0.24 and 2% CuSO4 were also effective, the latter however, proved slight harmful to the plants. Spraying with defoliants on Sept. 26 gave better results than treating plants on Sept. 16. Chemical defoliation decreased negligibly the frost resistance of Ligusturm vulgare shrubs.
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