Prevention and Control of Black Rot Disease in Cold Orchid
Cold orchid, as a rare orchid variety, the prevention and control of black rot disease is the key to its maintenance. This disease has the characteristics of rapid transmission and strong destructiveness, and if not handled in time, it can lead to the necrosis of the entire plant. This article deeply analyzes the pathogen characteristics and provides a scientific prevention and treatment plan.
Typical Characteristics of Black Rot Disease in Cold Orchid
Early Infection Signs
Yellowish-brown spots appear on the lower surface of the leaves, which are about 2-5mm in diameter and appear moist. At this time, the base of the pseudobulb begins to show transparency, which is the golden period for treatment.
Mid-term Lesion Manifestation
The spots expand to 1/3 of the leaf area, and the center of the lesion turns blackish-brown. Squeezing the lesion can see pus-like exudate, accompanied by a distinct foul smell. At this time, the diseased plants need to be isolated immediately.
Late Infection Characteristics
The pseudobulb is completely blackened and dehydrated, and the leaves fall off from the bottom up. The lesions dry up to form sunken holes, and the success rate of treatment at this time is less than 20%.
Five-step Systematic Prevention and Control Plan
Physical Isolation Measures
Immediately cut off the infected part when the lesion is found, and the incision needs to exceed the edge of the lesion by 2cm. Use a flame disinfection tool, and the excised tissue needs to be sealed and incinerated.
Chemical Control Plan
Use 0.15% copper sulfate solution for atomized spraying in the early stage, and in the middle and later stages, alternate the use of 50% wettable powder of fungicide Dan together with 80% wettable powder of Da Sheng M45 at 400 times and 500 times dilution, respectively, twice a week for three weeks.
Environmental Control Points
Keep the air circulation rate greater than 0.5m/s, and control the relative humidity between 55-65%. It is recommended to install a laminar flow circulation system to avoid leaf积水 for more than 2 hours.
Preventive Treatment
Spray 500 times dilution of Zinc while Pu every month during the growing season, and use 150 times dilution of Fumigation Double when changing pots to soak the roots. It is recommended to establish a disease warning log to record temperature and humidity changes.
Nutritional Enhancement Plan
Increase the application of calcium and magnesium elements to enhance cell wall strength, and combine with seaweed extract to enhance disease resistance gene expression. Avoid excessive nitrogen fertilizer causing虚长.
Through the three-dimensional prevention and control system of physical isolation + chemical control + environmental regulation, the incidence of black rot disease can be effectively reduced by 85%. It is recommended to establish a regular inspection system to detect and handle early. Combine with intelligent environmental monitoring equipment to achieve precision disease prevention.