Lilac (Syringa vulgaris L) seedlings are commonly grown in many seedling nurseries in Michigan. Typically seedlings are lifted in the fall and stored prior to shipment or stored by the customer. A major problem in field production of lilacs is that seedlings often retain their leaves late in the fall. If the leaves are not removed prior to storage or shipment, the seedlings will mold and deteriorate. Therefore, growers must spend additional labor to remove the leaves, often by hand. The goal of this research was to evaluate chemical alternatives to defoliate lilac seedlings in field nurseries. Two on-farm research trials were conducted in 2001 and 2003 in cooperation with a seedling grower in Saugatuck, MI. In Experiment 1, Florel (1/2 and ¼ dilution) and chelated copper (0.5% and 1% solution) were sprayed by and onto lilac in the seedling bed. Florel and chelated copper effectively reduced leaf area of lilac seedlings. Less than 20% of the initial leaf area remained on the 1% copper and ½ Florel-treated seedlings. The ½ Florel and 1% chelated copper completely defoliated 67% and 40% of the seedlings, respectively, whereas only 17% on the control seedlings lost all their leaves prior to lifting. Both levels of Florel and the 1% copper treatment reduced growth of seedlings after planting. In experiment 2, we applied chelated copper treatments at varying rates (0.25% and 0.5%) and times (1 application and 2 applications) using the cooperators' spray equipment. Repeated applications of chelated copper were more effective in reducing seedling leaf area than a single application at both concentrations tested.
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