Common Diseases and insect pests of Cymbidium and their Control

The Japanese hybrid Cymbidium has been cultivated in Xiamen overseas Chinese introduction Garden and colorful Orchid Flower for 16 years. In the process of cultivation, we have encountered many diseases, insects and small animals. As a researcher, I will observe and record the situation of diseases and insect pests and control countermeasures to make a summary, here to provide Lanyou as a reference. Cymbidium is cultivated in an excellent ecological environment, which requires high air humidity, and the general relative humidity should reach 80% to 90%. However, when the humidity is high, poor ventilation, poor air flow and lack of light will also cause the occurrence and spread of diseases and insect pests. The main common diseases and insect pests in this area are as follows:

First, diseases: there are mainly blight, soft rot, root rot, anthrax, leaf blight, toxin disease and so on.

(1) epidemic diseases:

Due to different locations and different diseases, the epidemic disease is also divided into black rot, heart rot, stem rot, quenching disease and so on, which occurs all the year round in Xiamen. In the case of high temperature, excessive watering and poor ventilation in greenhouse, a large amount of water accumulated in the leaf tip, which is most likely to cause the disease for a long time. The peak period of the disease is from June to August every year. It can be damaged from seedling to flowering plant, especially at seedling stage, new bud and heart leaf. It is caused by two closely related fungi-Phytophthora blight (Phytophthoracactorum) and ultimate Pythium (Pythiumw1tmum). Phytophthora is easy to cause root rot, quenching, root neck rot, and the ultimate Pythium is also easy to cause root rot and quenching disease. Once these diseases are not treated in time, they will quickly spread to the roots and bulbs, so it is a terrible and destructive disease of Cymbidium, which is transmitted and spread by spores through water droplets splashed during watering.

Prevention and control methods:

1. Environmental control: the blue shed should be ventilated and ventilated and the light should be adequate. During the onset of the disease, we should strictly control the water, remove diseased leaves and diseased plants in time, and avoid spraying water from top to bottom.

2. Once the infected plant is found, remove the diseased tissue immediately, at the same time, cut off about 1 inch of the uninfected tissue, and remove the whole plant if the damage is serious.

3. Scissors and other appliances should be strictly disinfected.

4. Chemical treatment: it can be sprayed with 80% Zn-mn Naipu 500 times solution. The diseased plants can also be sprayed with 8-hydroxyquinoline sulfate of 1Rau 2000, or the diseased plants can be soaked in o-phenylphenol sodium solution for 1 hour and repeated treatment within 3 to 7 days if necessary.

(2) soft rot: soft rot usually affects the leaves, buds and bulbs of Cymbidium, which can occur from spring to autumn in a year, and is rarely found in winter, sometimes accompanied by blight, but not too serious. It is caused by a bacterium called Erwiniachrysanthem, which has a wide range of hosts and can be harmful in orchids. The way of invasion is mainly through the wound or natural stomata. In the hot and humid blue shed, the disease spreads very quickly. At 100% relative humidity and temperature of 30 ℃, the invasion process was completed after three hours of artificial inoculation. The manifestation of the disease is similar to that of the epidemic disease, which makes it difficult to distinguish those who raise orchids. Because the two diseases are different in nature, the use of drugs is also different. In the field, our discrimination is mainly based on the observation of pulling out the decaying part of the disease: the decaying tissue of the disease has no juice or less juice, no fishy smell, squeeze the juice into a cup of water, and no diffusion of cloudy matter is found. On the other hand, the cells in the epidermis of soft rot disease are decomposed into water-like juice, which contains countless white bacteria mud, and there is a lot of juice. At the same time, there is the stench of fishy smell. Drop by drop in the clear water cup, you can see the cloud-like turbid matter spreading around.

Prevention and control methods:

1. Environmental control and treatment of diseased plants: same as Article (1) above, special attention should be paid not to pollute healthy plants with the juice of bacterial mud.

2. Chemical treatment: general pesticides are ineffective against soft rot, so once the disease occurs, we have to abandon the diseased plant. Therefore, it is mainly to take preventive measures, with 40% steel fast Dening 400 times liquid spraying effect is good. You can also spray 68.8% polychain microelement or 18.8% chain microelement 1000 times every 7 to 10 days for 3 to 4 times in a row. These drugs can be used alternately to prevent the plants from developing drug resistance. (Wu Lianxing)