Using Florel to Control Upper Leaf Necrosis and Reduce Height in Pot Oriental Hybrid Lilies

Air movement on the leaves is the classic way to increase calcium uptake into leaves or fruit. Thus, an effective method to reduce ULN is to use fans and blow air on the plants, with enough force and volume that the leaves move slightly. Another way to increase calcium in the leaves was to expose the leaves to air. In one experiment, we artificially unfolded leaves from the stem (when plants were about 12” tall) as a way to increase transpiration (water loss) from the leaf and therefore increase the amount of calcium moved into the leaf. When leaves were gently bent back from the stem (Fig. 2) once per day the ULN at crop maturity almost completely disappeared, and if it was done twice per day, no ULN was seen, even on 16/18 cm bulbs which are normally very sensitive to ULN (Figure 3). Interestingly, the plants that had unfolded leaves were shorter than the controls (Fig. 3). Probably, this was due to the mechanical stress caused by the unfolding. In many plants, such mechanical stress produces small amounts of ethylene and causes shorter, thicker and stronger stems.