How to prevent and treat jasmince leaf spot disease
I. Recognizing the typical symptoms of jasmince leaf spot disease
As an aromatic ornamental plant, jasmince is often troubled by leaf spot disease during maintenance. Initially, brown needle-like spots appear on the surface of the leaves, and as the fungal hyphae spread, they gradually form irregular lesions with diameters of 3-8mm. The characteristic appearance of the lesions is a central yellowish-brown papery area, surrounded by a light-colored halo, and black sporulation can be seen in the later stage. If not treated in time, it will lead to the yellowing and falling off of the entire plant's leaves.
II. Analysis of the occurrence pattern of jasmince diseases
2.1 Overwintering characteristics of the pathogen
The pathogen (Cercospora jasminicola) overwinters in the form of mycelium in diseased leaves, and begins to sporulate when the temperature rises to 18°C in the following spring, spreading and infecting new leaves with the help of wind and rain.
2.2 Seasonal disease cycle
In the Yangtze River Valley, symptoms appear in early May, peak during the plum rain season from June to August, and continue until late September. The fastest spread occurs when the daily average temperature is between 25-28°C and the relative humidity is greater than 80%.
III. Comprehensive control system for jasmince leaf spot disease
3.1 Cultivation management control
• Timely removal and incineration of diseased leaves• Increase application of phosphorus and potassium fertilizers (N:P:K = 1:2:3) to enhance resistance• Maintain a plant spacing of 40cm or more to ensure ventilation and light penetration
3.2 Chemical control program
Prevention period: Spray 12% green copper 600 times liquid before germinationEarly stage of disease: Alternate between 40% Topsin M 500 times liquid and 50% thiophanate-methyl 800 times liquid, with a 7-day interval for 3 consecutive spraysDuring the rainy season: Mix with organic silicon additives to improve the adhesion of the medicine
3.3 Ecological regulation measures
• Build a rainproof shed to reduce humidity• Cover the roots with pine bark to adjust the soil pH to 6.0-6.5• Intercrop with mint and other fungicidal plants to form an ecological barrier
IV. Key points of systematic management of jasmince diseases
It is recommended to establish a full-year control calendar: clean and disinfect the garden in March, spray protective agents in April, focus on monitoring from May to September, and spray lime sulfur after pruning in winter. By combining physical, chemical, and biological control methods, the incidence of diseases can be reduced by more than 75%.