Lily blight

Blight is an important disease of lily, which is widely distributed, mostly occurs in the south, and occasionally occurs in the protected areas in the north. Usually 5% 10% of diseased plants affect the production of lilies to a certain extent, which can reach more than 30% when heavy, resulting in plant death and significantly affecting the yield and quality of lilies.

Symptoms: the disease can affect all parts of the lily. The stem infected with disease, initially showed water-immersed light brown to green-brown rot, and gradually expanded up and down, causing the plant to die or fold. Leaves infected with disease, the initial water immersion-like small spots, and later developed into gray-green to dark green spots, eventually causing the disease leaves to rot or die. After infection, the floral organ showed yellowish brown to dark brown soft rot, and the damp air produced a sparse white mold layer on the surface of the diseased tissue, namely the pathogen cyst peduncle and sporangium. The corm infected with the disease began as a water-immersed yellowish brown necrotic spot, then expanded and rotted, resulting in sparse white mold on the surface of the diseased tissue.

Pathogen: Phytophthoracactorum (Leb.etCohn) Schrotr belongs to flagellum, Phytophthora. The mycelium of the pathogen had few branches, 2 × 6 μ m wide, and the sporangium was ovate to subglobular, with a size of 33.5 μ m × 28 μ m × 34 μ m. The oospore is spherical with a diameter of 27033.5 μ m.

Disease regularity: the pathogen overwintered in the soil with chlamydospores or oospores. When the conditions are suitable, chlamydospores or oospores germinate, invade the host and cause disease, and a large number of sporangia are produced in the diseased part. after germination, zoospores or sporangia are released to germinate directly for re-infection. The temperature is 26-28 ℃, and the weather is humid or rainy. Poor drainage after rain and thick and tender plants in the field are beneficial to the occurrence and development of the disease.

Prevention and cure method

1. Use high ridge or high border cultivation, fine soil preparation, repair field drainage ditch, in order to timely drainage after rain.

two。 Reasonable close planting, application of fully mature organic fertilizer and appropriate application of potassium fertilizer to enhance plant disease resistance.

3. Strengthen the field management, dig out the diseased plants as soon as possible, and bury them deeply outside the field. Proper control of watering after the onset of the disease.

4. Timely application of pesticide in the early stage of the disease, and dust application technology had better be adopted in the protected area.