What are the common diseases of orchids? A detailed guide to prevention and treatment methods
Orchids are one of China's famous flowers. Their fragrance is elegant and noble, and their blooms are small and exquisite, earning them the title of "gentleman among flowers." However, when orchids suffer from pests and diseases, their ornamental value is greatly affected. The common pests and diseases of orchids include: southern blight, anthracnose, and leaf blight.
Orchid southern blight
Symptoms
The disease is most severe when watering is excessive or ventilation is poor, and seedlings that have just been planted are especially vulnerable. Infected areas develop brown lesions, which expand rapidly in high-temperature, high-humidity conditions and eventually appear as dark brown spots.
Prevention and treatment methods
Attention should be paid to ventilation and light transmission, and good drainage of the potting soil for prevention. After the disease occurs, the contaminated potting soil can be removed and pentachloronitrobenzene powder or lime sprinkled on.
Orchid anthracnose
Symptoms
Plants grown too densely, with poor ventilation, water imbalance, or wounds from injury are prone to the disease.
In the early stages of infection, obvious small brown sunken spots appear on the orchid plant, which then gradually expand to form round, irregular lesions. In severe cases, necrosis appears in the center of the lesions.
Prevention and treatment methods
Do not plant too densely. Increase light exposure, and ensure good drainage and ventilation.
Grow strong seedlings, and do not frequently move the plants, so as to avoid damage and infection. Apply more phosphorus and potassium fertilizer to strengthen the plant's disease resistance.
Promptly cut off diseased leaves, and apply 1/500 dilution of Daconil solution or 1/800 dilution of Wanjunqing to the wounds. Spray once a week with 1/1000 dilution of thiophanate-methyl or carbendazim solution.
Orchid leaf blight
Symptoms
Small black spots appear at the leaf tips and gradually expand into irregular lesions. The edges of the lesions become dark brown, while the centers are light grayish-brown. In severe cases, they spread across the entire leaf, which finally withers and falls off.
Prevention and treatment methods
Cut off the diseased leaves and spray with 500 dilution of Daconil-45 or 1000 dilution of Haoshengling.
For infected plants, avoid rainwater or temporarily stop watering to prevent the condition from worsening.
Spray once daily with 500 dilution of Daconil-45 as a preventive measure.