Hawthorn, with its sweet and sour taste, actually grows on hawthorn trees. In some areas of China, the cultivation area of hawthorn trees is considerable. Circular spot root rot is one of the important reasons causing the death of hawthorn trees. Let's learn about the prevention and control methods of hawthorn circular spot root rot.
Symptoms
The roots turn brown and die first, and reddish-brown circular lesions appear around the base of the roots. In severe cases, the lesions merge, rotting deep into the woody part, leading to the death of the entire root.
Transmission and Conditions for Occurrence
The pathogen causing this disease can live saprophytically in the soil for a long time. When the roots of hawthorn trees grow weak, the pathogen invades and causes disease. Orchards with heavy and compacted soil, excessive salinity, long-term drought and lack of fertilizer, serious soil erosion, severe biennial bearing, and improper management are more prone to the disease.
Prevention and Control Methods
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Enhance cultivation management: Improve tree vigor and resistance to disease. Improve orchard drainage and irrigation facilities to ensure drought resistance and drainage; improve soil structure to prevent soil erosion, and deep plowing can be carried out in suitable orchards. Cultivate and weed in a timely manner during the growing season and maintain soil moisture; conduct proper pruning to regulate tree fruiting and avoid biennial bearing; orchards with poor fertility should use multiple green manures and adopt formula fertilization techniques.
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Treat diseased trees: In spring and autumn, expose the roots by loosening the soil, scrape off or remove the diseased parts of the roots. During the exposure period, avoid watering or rainwater in the tree holes. Expose the roots for 7-10 days, scrape off the lesions, and then apply Bordeaux mixture or 5% Bordeaux mixture or 45% crystal sulfur mixture at a dilution of 30 times for root drenching. Alternatively, apply 50% carbendazim at a dilution of 1000 times or 50% thiophanate-methyl wettable powder at a dilution of 300 times on the wounds, which also has a good preventive effect.
