How to Treat Black Rot Disease in Succulents
Succulents are loved for their charming shapes, but the black rot disease, which is highly prevalent in summer, often leaves growers at a loss. This disease, caused by the Fusarium fungus, is characterized by its rapid spread and high fatality rate, requiring a grasp of scientific treatment methods and preventive systems to effectively address it.
Causes of Black Rot Disease and Early Identification
Environmental Characteristics of Fungal Infection
High temperature and humidity are the main triggers for black rot disease. When the temperature exceeds 30℃ and air circulation is poor, the latent Fusarium fungus in the soil invades quickly through root wounds. Initial symptoms include brown, water-soaked spots appearing at the base of the leaves, which can spread to the stem within 48 hours.
Complete Treatment Process for Black Rot Disease in Succulents
1. Excision of Lesions and Disinfection
Use a knife disinfected with alcohol to斜切 the affected area 2cm from the edge of healthy tissue. After applying carbendazim powder to the wound, place it in a cool, shady place to dry. It is recommended to use a broad-spectrum fungicide containing pyraclostrobin for a full plant soak.
2. Proper Potting and Soil Replacement Procedures
The original potting soil must be discarded entirely, and new soil should be mixed in a 7:3 ratio of granular soil to peat soil. It is recommended to use red pottery as the pot material, with a 3cm thick layer of volcanic stones at the bottom as a drainage layer. Do not water for 72 hours after potting.
3. Backup Propagation Emergency Plan
Select healthy top leaves for leaf insertion, using vermiculite as the propagation medium, and maintain an environmental temperature of around 25℃. This method can achieve a survival rate of over 90%, preserving the chance for the plant to regenerate.
Four Key Preventive Measures for Black Rot Disease
1. Environmental Control System
In summer, maintain a day-night temperature difference of more than 8℃, use shade nets to control light intensity to within 15000Lux, and install circulating fans to ensure air flow is greater than 0.3m/s. When the humidity monitor shows more than 70%, immediately strengthen ventilation.
2. Scientific Watering Strategy
Supply water using the immersion method, with each immersion lasting no more than 10 seconds. Extend the watering interval to 15-20 days, choosing to water between 6-8 am to avoid water accumulation in the leaf heart. It is recommended to use a moisture meter to monitor soil moisture.
3. Soil Improvement Plan
Add 5% bamboo charcoal granules each quarter to enhance antibacterial properties, and mix 3% sulfur powder to adjust the pH to 6.0-6.5. Regularly use Bacillus subtilis for biological control to reduce the risk of bacterial growth.
4. Regular Inspection System
Establish a weekly inspection mechanism, focusing on the base of the stem and the back of old leaves. Isolate any suspicious spots immediately and use systemic fungicides for preventive root drenching.
Through systematic treatment methods and preventive systems, the cure rate for black rot disease in succulents can be increased to over 85%. The key is to maintain the continuity of environmental monitoring and the规范性 of maintenance operations to keep succulents safe during the summer.