Recent heavy rainfall has led to the occurrence and spread of collar rot disease in many apple orchards. Collar rot disease can cause harm to both the leaves and fruits of apple trees. Its occurrence is closely related to temperature and humidity. Let's discuss the preventive measures for apple collar rot disease.
Causes of Apple Collar Rot Disease
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High temperature and humidity, prolonged rainfall.
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Aging of fruit trees, low pruning in the past, with lower branches bearing fruits close to the ground.
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Due to the rare occurrence of apple collar rot disease in previous years, the soil-borne pathogen load has accumulated over the years without any preventive measures, providing a source of infection.
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Misdiagnosis of apple collar rot disease as anthracnose or brown spot disease, missing the critical period for prevention and control.
Preventive Measures for Apple Collar Rot Disease
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Orchard Cleaning: After apple trees are infected with collar rot disease, winter cleaning of the orchard is necessary. Burning or burying diseased branches, leaves, and fruits remaining on the branches or the ground is the most reliable method to prevent future orchard harm.
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Ground Cover: Collar rot disease is a soil-borne disease. The pathogen overwinters in the soil. After the weather warms up the following year, one of the main ways for the disease to spread is through splashing rainwater. Therefore, covering the tree base with weeds or straw can prevent rainwater splashing and reduce the spread of pathogens.
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Water and Fertilization Management: Proper water and fertilizer management in the orchard is essential. During autumn fertilization, organic fertilizers and microbial agents should be applied to disinfect the soil and reduce the incidence of soil-borne diseases. During heavy rainfall, excess water should be drained promptly to prevent the spread of pathogens.
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Pruning: It is recommended to prune apple trees to at least 80 centimeters above the ground during pruning. This way, the lower branches can be further away from the ground, reducing the risk of collar rot disease infection. Additionally, when training branches, the angle of the lower branches should not be too wide to keep the fruits away from the ground.
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Soil Disinfection: Mix 1 kilogram of carbendazim with 1 centimeter of calcium copper sulfate and some fine sand. Sprinkle this mixture throughout the orchard to achieve effective control.
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Chemical Control: Spray 100-fold dilution of copper sulfate or calcium copper sulfate on the ground; after flowering and before bagging, spray 2500-3000-fold dilution of fenhexamid 50% wettable powder; after bagging, spray 800-fold dilution of captan 85% wettable powder; or apply 100-fold dilution of copper sulfate to the trunk, or use for irrigation.
Above are the preventive measures for apple collar rot disease. Also known as neck rot or crown rot, collar rot disease is one of the significant diseases affecting apple trees, severely impacting their growth, development, and fruit quality. Orchard growers should pay attention to prevention and control.
