Identification of Symptoms and Control Methods for Root Rot in Dendrobium

Root rot is a common root disease in the process of cultivating Dendrobium, and it can occur whether in home pot culture or greenhouse cultivation. After the disease develops, the root system gradually rots, and its ability to absorb water and nutrients drops noticeably; in severe cases, it causes the entire plant to wither and die, making it one of the important factors affecting the survival rate of Dendrobium.

Identifying this disease can start with the condition of the roots. Healthy Dendrobium roots are usually white or pale green, plump and firm; after infection, the root system turns brown or dark brown, becomes soft and mushy, and the outer layer peels off easily when pulled lightly. The aboveground parts often show yellowing leaves that lose their luster, weakened growth of new shoots, and over time the base of the stem may also rot along with them.

Root rot is mostly caused by fungal infection, with high temperature and high humidity, overly frequent watering, and poor drainage of the growing medium being the most common triggers. Long-term water accumulation in the pot, poor ventilation, or root wounds during transplanting and division becoming infected by pathogens can all create conditions for the disease, and extra attention is needed especially during the hot, humid rainy season.

Daily care should focus on prevention. The growing medium should be loose, breathable and well-draining; watering should follow the principle of watering when dry and withholding when wet, avoiding long-term moisture in the pot, while keeping the environment ventilated and appropriately reducing water in the rainy season. Once a diseased plant is found, it should be unpotted promptly for inspection, the rotted roots cut off, soaked and disinfected in a fungicide solution such as carbendazim, dried, and then repotted in fresh, clean medium; the diseased plant should also be placed separately from healthy plants to prevent cross-infection.