Identification and control of anthracnose of Cymbidium, and mastery of topdressing methods of edible fungi.

1. Characteristics of symptoms

Colletotrichum anthracnose is a common fungal disease in the cultivation and management of Cymbidium, both adult and young plants can be damaged. The disease mainly infects leaves, especially the leaf margin of the middle and lower leaves of the plant is more vulnerable. At the beginning of the disease, brown spots appeared on the leaf surface, and then gradually expanded into round or oval, slightly sunken, with wheel-like markings. In the later stage, the disease spot gradually dried up, and many small black spots were scattered on it. When the disease is serious, the damage of the whole plant causes the leaves to blacken and wilt.

Second, occurrence regularity

The pathogen overwintered as hyphae in the host residue or soil, and the disease began to occur in the old leaves at the beginning of April of the following year. It developed rapidly when the temperature reached 22: 28 ℃ from May to June, and the disease was serious in the rainy season with high temperature and humidity. Bacterial spores are spread by airflow, wind and rain, watering and so on, and mostly invade from the wound. The disease is serious when the plant is partial to nitrogen fertilizer, lack of phosphorus and potassium fertilizer and poor ventilation and light transmission.

III. Prevention and control methods

1. Improve the environmental conditions, pay attention to ventilation and light, properly increase the application of phosphorus and potassium fertilizer in nutrition management, control the amount of nitrogen fertilizer, and improve the plant disease resistance.

2. The diseased leaves of the diseased plants were cut off in time and burned or buried deeply.

3. To improve the watering method, we should pour water from the edge of the flowerpot, and the drainage of the basin soil should be good, so as to reduce the humidity of the basin soil as much as possible.

4. At the initial stage of the disease, spraying 70% methyl topiramate wettable powder 1000-1500 times, or 60% anthrax Fumei wettable powder 800-1000 times, once every 7-10 days for 3 consecutive 5 times, can play a role in treatment and prevention.

(Ding Shimin, Department of Landscape Engineering, Weifang Vocational College)