Prevention and control of root rot of Cymbidium

It occurred in all the cultivation areas of Cymbidium, causing rot in the roots and even the death of the whole plant.

Symptoms: the damage of the plant begins from the root, brown necrotic spots appear on the fleshy root, which gradually expands and causes the whole root cortex to rot, and most of the rotten roots remain in the soil after pulling out the stem from the soil; the aboveground part shows that the leaves are dull and yellowing rapidly.

Disease regularity: the pathogen is fungus, Fusarium. The pathogen attached to the diseased and residual tissue spread in the soil. When the orchid is poorly managed, such as lack of fertilizer, especially extreme lack of nutrition after anthesis, poor drainage of nursery or flowerpot, damp and stagnant water, or drought and water shortage during the growing period, freezing injury, and weak growth of insect pests, the disease is easy to be infected. However, the disease is serious when the soil is high humidity for a long time, the environment is muggy, the air is not ventilated and the humidity is high.

Prevention and control methods:

(1) strengthen cultivation management. The suitable temperature for the growth of Cymbidium is 15-25 ℃, the cold resistance is poor, the heat resistance is not strong, and the high temperature in summer is in a semi-dormant state. In winter, it is necessary to go through the semi-dormancy period, that is, the temperature is kept at 8: 10 ℃. If the temperature is lower than 5 ℃, it is easy to suffer frost injury. If the temperature is higher than 15 ℃, the dormancy is broken, which is disadvantageous to flowering. Like half-overcast, avoid the scorching sun. Like loose, fertile soil rich in humus. Slightly able to withstand drought but not stagnant water. Planted in deep pots. Spring and autumn is its growing season, basin soil can be slightly wet, but not too wet or even stagnant water, once every 20 to 30 days to apply liquid fertilizer. Topdressing is suspended at the height of summer and winter, and the basin soil should be on the dry side. Phosphate fertilizer was applied once 20 days before flowering. Attention should be paid to ventilation in spring, summer and autumn, and hot sun exposure should be prevented in summer. Put it in the sunny place indoors in winter, the room temperature should not be lower than 5 ℃, and the heart should be protected from rain in summer. Usually water to avoid spraying from above.

(2) dig out the diseased plant in time, rinse with clean water, cut off the diseased fleshy root, sterilize it in 200 times of 50% carbendazim wettable powder for 3 minutes, and then air for 2 days for 3 days; the original basin soil is discarded and the old pot is disinfected (burned or immersed in 1% copper sulfate solution for 24 hours) or replanted with new soil instead of new pot.