Control Methods for Leaf Blight in Lily Cultivation
Symptoms: Circular or oval lesions form on the leaves, varying in size, with a length of 2 to 10 mm or more. They range from pale yellow to light brown. In some varieties, the spots are light brown, surrounded by a distinct reddish-purple margin, and under humid conditions the spots are quickly covered with a layer of gray mold. When the lesions dry, they become thin, brittle and transparent, generally appearing grayish-white. In severe cases, the entire leaf dies. When the stem is infected, it rots and breaks at the site of infection, and the buds turn brown and rot. Spots on the flowers are brown and, when moist, quickly turn into a sticky mass covered with a gray mold layer. When young plants are infected, the growing point usually dies. However, the plant can regrow in summer.
Pathogen: The pathogen is a fungus of the genus Botrytis, Botrytis elliptica (Berkeley) Cooke. The conidia are oval. Sometimes Botrytis cinerea Pers. can also harm lilies, but it mainly causes flower rot.
Transmission route: The fungus overwinters as mycelium or sclerotia on fallen diseased plant debris, and in the following year produces conidia that infect and cause damage, and can cause repeated infections multiple times; disease is likely to occur when the greenhouse is excessively humid. Disease is severe when plants are too densely planted, and severe when nitrogen fertilizer is applied excessively.
Control methods:
1. Horticultural control: In autumn, remove and destroy the aboveground parts of plants cultivated outdoors; remove diseased leaves at the first sign of disease to reduce sources of infection.
2. The greenhouse should be ventilated and have sufficient light. Watering should be done at a time when moisture on the leaves dries easily, preferably by watering from the edges, avoiding wetting the leaves.
3. Chemical control: You can choose 50% carbendazim or 70% carbendazim or 70% thiophanate-methyl wettable powder at 500 times dilution. If necessary, you can choose 50% procymidone or 50% iprodione and 50% vinclozolin wettable powder at 1000 to 1500 times dilution plus 80% carbendazim wettable powder at 600 times dilution for good results. Spray 40 to 50 kg of solution per 667 sq m each time. Focus on spraying the newly grown leaves and the surrounding soil surface, and spray 2 times consecutively.