Comprehensive Management Techniques for Bulbous Flowers, Part 19: An Introduction to Edible Mushroom Cultivation Techniques

Leaf scorch, bud drop and bud shrivelling: Bud drop in lilies occurs when the flower buds have grown to 1 to 2 cm long. The buds turn pale green, and at the same time the pedicel connecting them to the stem shortens, after which the flower buds drop off. In spring, the lower buds are affected first, while in autumn the upper buds drop first. Bud shrivelling occurs throughout the entire growing period. The buds turn completely white and dry out, and these dried buds sometimes drop off. If bud shrivelling occurs early in the plant's development, tiny white spots will later appear on the leaf axils. Cause: Bud drop occurs when the plant does not receive sufficient light. Under conditions of insufficient light, the stamens within the bud produce ethylene, causing bud abortion. If the root system's living conditions are poor, such as dry soil, bud shrivelling will occur. Control methods: Do not cultivate varieties prone to bud drop in environments with poor light. To prevent bud shrivelling, the bulbs must not dry out during cultivation. Ensure that the bulbs have a good root system and let them grow under the best possible conditions, especially regarding light and transpiration. Symptoms: Leaf scorch occurs before the flower buds appear. First the young leaves curl inward, after which greenish-yellow to white spots appear on the scorched leaves. If the scorch is mild, the plant can continue to grow, but if the scorch is severe, the white spots can turn brown and the leaves bend. Eventually all the leaves and young buds drop off, and the plant stops developing. Cause: Leaf scorch occurs when the balance between water uptake and transpiration is disrupted; this is the result of calcium deficiency in the young leaf cells caused by insufficient water uptake or transpiration. A poor root system, excessively high soil salt content, the upper part of the plant growing too fast relative to the root system, and rapid changes in relative humidity in the greenhouse can all cause leaf scorch. Sensitivity varies greatly depending on variety and bulb size; large bulbs are more sensitive than small bulbs. Control methods: Pests and diseases damaging the root system should be controlled. The soil should be kept moist before planting. It is best not to plant susceptible varieties; if such varieties must be used, large bulbs should be avoided as much as possible. Plant bulbs with a good root system, at a suitable planting depth, with 6 to 10 cm of soil above the bulb. Avoid large fluctuations in temperature and relative humidity in the greenhouse, and try to keep relative humidity at around 75%. Prevent excessively fast growth. For the more sensitive Asiatic hybrids, keep the greenhouse temperature at 10°C to 12°C for the first 4 weeks, while for Oriental hybrids the temperature should be 15°C for the first 6 weeks, and box cultivation with a rooting room is recommended. Avoid excessive transpiration by shading, and on sunny days water can be sprayed several times a day. (Part 19) (International Flower Bulb Centre, the Netherlands)