Diseases of White Orchid and Their Control
White orchids are deeply favored by horticulture enthusiasts for their elegant floral posture, but they often encounter three major diseases during their growth process. This article focuses on the three typical symptoms of (T-J) disease, root rot, and chlorosis, combining over 20 years of gardening experience to systematically analyze the characteristics of onset and scientific prevention and treatment methods, helping you create healthy white orchid plants.
Comprehensive Control of White Orchid (T-J) Disease
Symptom Identification Features
During the high-incidence period from June to August each year, the leaves initially show needle-like yellow spots, which expand into circular/semicircular brown spots as the disease progresses, with the center of the lesion showing grayish-white necrosis and the edges having a distinct dark brown halo. When humidity is >80%, the disease leaf rate can reach over 70%.
Three-Level Prevention and Control System
1. Environmental Control: Use siphon watering method to keep the leaf surface dry. 2. Biological Control: Spray Bacillus subtilis 500 times solution before the onset of the disease. 3. Chemical Intervention: Alternate the use of 25% Prochloraz emulsion 1500 times solution and 80% Mancozeb 600 times solution, 7 days/interval for 3 consecutive times.
Systematic Management of White Orchid Root Rot Disease
Symptom Development Pattern
Initially, the plant shows slow growth, and as the disease worsens, typical symptoms such as yellowing of new leaves and falling of old leaves appear. Detection shows that the main pathogen is Fusarium, with a soil-borne disease transmission rate of 92%.
Stereoscopic Prevention and Control Plan
1. Substrate Improvement: Mix perlite: decomposed leaf soil: vermiculite in a ratio of 3:5:2. 2. Physical Treatment: Sterilize the cultivation soil in a microwave oven at high temperature for 10 minutes. 3. Medicament Root Irrigation: Use a double combination of Metalaxyl + Mefenoxam 1500 times solution, treated at 10-day intervals.
Accurate Correction of White Orchid Chlorosis Disease
Physiological Imbalance Diagnosis
When soil pH > 7.5, chlorophyll synthesis is hindered, showing net-like yellowing (green veins/yellow mesophyll). Detection data shows that symptoms appear when the effective iron content is <4.5mg/kg.
Targeted Repair Technology
1. Emergency Treatment: Spray chelated iron 2000 times solution on the leaf surface (3 times/week). 2. Soil Improvement: Adjust the pH with sulfur powder at 1kg/m³. 3. Long-Term Maintenance: Apply mature rice water (diluted 10 times) monthly to maintain an acidic environment.
By establishing a disease warning mechanism (regularly testing soil EC values and leaf SPAD values) combined with precise prevention and control measures, the incidence of white orchid disease can be effectively reduced by over 85%. It is recommended to carry out systematic maintenance every quarter, especially paying attention to disease prevention before and after the rainy season, to ensure the healthy growth of the plants.