Symptoms, Identification and Control of Lily Leaf Scorch

Lily, also known as Qiangshu, Fanjiu, Shandan, Daoxian, Chongmai, Zhongting, Moluo, Chongxiang, Zhongfenghua, Baihesuan, Dashifusuan, Suannaoshu, Yehehua and so on, is a perennial herbaceous bulbous plant of the genus Lilium in the family Liliaceae, native to China and mainly distributed in the temperate regions of the Northern Hemisphere such as East Asia, Europe and North America. At least 120 varieties have been found worldwide, of which 55 are native to China. In recent years there have been many new varieties produced through artificial hybridization, such as Asiatic lilies, Oriental lilies, fire lilies and so on. The bulb is rich in starch, edible, and also used medicinally.

Lily leaf scorch, also called leaf blight or leaf burn. The specific symptoms are: leaf scorch occurs before flower buds are visible to the naked eye; before budding, the young leaves curl slightly inward, and after a few days yellow-green to white spots appear at the leaf tips. In severe cases, the white spots can turn brown and scorched, and the leaves and younger buds will drop off. The main cause is an imbalance between water uptake and transpiration in the plant, related to excess manganese salts and aluminum salts in the soil, poor root development, calcium deficiency in young leaf cells, and rapid changes in greenhouse relative humidity; it is also related to variety and bulb size, with large bulbs being more susceptible than small bulbs.

Control methods: controlling pests and diseases that damage the root system, regulating soil moisture, selecting suitable varieties, and using small-sized bulbs as much as possible are the main measures for controlling leaf scorch. At the same time, after planting the bulbs, the covering soil should be kept at 6 cm to 10 cm, the greenhouse relative humidity should be kept between 75% and 85% as much as possible, large differences in temperature and relative humidity should be avoided, and shading and water spraying in summer should be used to avoid excessive transpiration and prevent overly rapid growth.

Note: Lilies prefer cool conditions and are relatively cold-tolerant. They grow poorly in high-temperature areas. They prefer dry conditions and are afraid of waterlogging.

Excessively high soil moisture causes the bulbs to rot and die. They are not strict about soil requirements, but in deep, fertile, loose sandy loam the bulbs are white in color and thicker in flesh. Heavy clay soil is not suitable for cultivation. The root system is thick and well developed, and tolerant of fertilizer.

After emerging in spring, they require sufficient nitrogen nutrition and adequate phosphorus and potassium fertilizer, N:P:K=1:0.8:1, and the fertilizer should be mainly organic fertilizer. Continuous cropping should be avoided, with a rotation once every 3~4 years, and the previous crop should preferably be legumes or grasses.