Pear tree rot disease, also known as sour skin disease, affects the branches of pear trees. It mainly occurs on lateral branches and main branches, where the infected area is prone to tearing, the cortical tissue becomes soft, and there is a smell of wine lees. Let's discuss the prevention and control methods for pear rot disease.
1. Symptoms
Pear rot disease is a fungal disease. It rarely affects tree trunks and small branches, mainly occurring on lateral and main branches. The sunny side and branch forks of large branches are prone to infection. In the early stage of the disease, the infected area appears water-stained, slightly raised, dark brown to reddish-brown in color, with a wine and sweet smell. When pressed with fingers, reddish-brown juice oozes out, and the infected area sinks slightly. Later, black wart-like structures develop on the infected area, gradually drying up and sinking, followed by cracking of the bark. The fungus generally only penetrates the surface of the bark. It does not occur in summer, and the disease is less severe in autumn and more prevalent in spring.
2. Occurrence Patterns
The fungus overwinters on the bark and becomes active again in early spring when the weather warms up, causing old scars to enlarge and new infections to occur. The fungus spreads through rainwater, entering the tissues through wounds. Extensive management and weakened tree vigor make trees more susceptible to the disease.
3. Prevention and Control Methods
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Enhance cultivation management to improve tree vigor and disease resistance.
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Minimize mechanical damage. After pruning, apply animal oil or paint to large wounds to prevent rapid moisture loss and aid healing.
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Combine winter pruning to remove diseased branches, dead fruit stalks, dead branch tips, and other dead tissues to reduce sources of infection.
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Scrape and treat infected areas. In summer and early spring, identify infected spots, apply fungicides, and scrape off diseased tissues.
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Spray eradication agents. In early spring, spray 100-fold dilution of 40% carbendazim wettable powder or 100-fold dilution of 5% Bordeaux mixture on large branches and main trunks to reduce pathogen populations and prevent disease occurrence.
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Apply whitewash for cold protection. In areas with strong sunlight, apply whitewash to tree trunks after autumn. The mixture consists of 1-2 parts table salt, 6 parts hydrated lime, and 20 parts water.
Above are the introduction and management practices for preventing and controlling pear rot disease. It's a major disease that pear orchards need to prevent in spring, as it affects the branches of pear trees. Planters should pay attention to prevention and control measures.
