Common Diseases and Control Methods of Orchids
As a representative of elegant flowers, orchids often encounter diseases during the maintenance process. This article systematically analyzes the characteristics of three typical diseases and provides targeted solutions to help orchid enthusiasts establish a scientific protection system.
Key Points for the Control of Orchid Sclerotium Blight
Recognition Features of Sclerotium Blight
Often occurs in newly transplanted seedlings, initially presenting as water-soaked brown spots. Under high temperature and humidity conditions, the lesion expands rapidly, forming black-brown necrotic patches, often accompanied by white mycelium.
Comprehensive Control of Sclerotium Blight
Adopt matrix disinfection prevention method: mix pearl rock with mature pine bark (3:7 ratio), and treat with 50°C steam for 30 minutes before planting. Immediately isolate the plant after the disease occurs, use pentachloronitrobenzene (1g/m²) for soil disinfection, and spray the leaf sheath with 0.1% copper sulfate solution.
Treatment Plan for Orchid (T-J) Disease
Development Process of (T-J) Disease
The typical symptom is the appearance of concentric ring-shaped lesions on the leaves, initially presenting as small brown spots, later expanding to circular sunken spots 2-5 cm in diameter, with dark brown elevated edges and central tissue necrosis and perforation.
Three-dimensional Prevention and Control of (T-J) Disease
Implement a three-level protection strategy: ① Physical protection: maintain a plant spacing of ≥25 cm; ② Nutritional regulation: apply potassium dihydrogen phosphate (800 times liquid) every month; ③ Chemical control: alternately use 25% propiconazole emulsion (1500 times liquid) and 70% methyl thiophanate (1000 times liquid), and spray protective fungicides before the rainy season.
Strategies for Dealing with Orchid Leaf Blight
Evolution Law of Leaf Blight
The V-shaped yellow spots appear from the leaf tip, expanding to 1/3 of the leaf area within 48 hours, with a distinct yellow halo at the border between healthy and diseased tissue, and black mold (conidial piles) appears in the later stage.
Systematic Treatment of Leaf Blight
Establish an environmental monitoring system: install a thermometer and hygrometer to maintain air humidity at 60-70%, and use a circulating fan to maintain an air flow rate of 0.3 m/s. The chemical control adopts a three-step method: cut off the diseased leaves → apply mancozeb paste → spray the whole plant with benomyl suspension (2000 times liquid).
By establishing a protection system focusing on prevention and supplemented by treatment, combined with precise temperature and humidity control, the incidence of orchid diseases can be significantly reduced. It is recommended to conduct systematic inspections monthly, establish a disease log, adjust the maintenance plan in line with seasonal changes, and achieve scientific and meticulous orchid health management.