Apple russeting is a physiological disease caused by adverse external conditions. Its main symptom is the formation of cork-like layers that resemble metal rust on the surface of the apple, significantly affecting its appearance and commercial value. So, what types of apple russeting are there, and how can they be effectively prevented? Let's find out.
Types and Prevention of Apple Russeting
1. Frost Russeting
Frost russeting mainly occurs due to late spring frosts or low temperatures during the flowering period, which cause damage to floral organ cells and subcutaneous cells, leading to frost russeting.
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Prevention Methods:
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Increase the application of organic fertilizers, microbial fertilizers, and compound fertilizers to enhance tree nutrition and improve frost resistance.
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Cover the tree base with plastic film, straw, crop stalks, or weeds to keep the soil warm and slow down soil temperature rise.
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Spray anti-frost agents before low temperatures arrive. Use 0.3% potassium dihydrogen phosphate + 0.3% urea or other protective agents like 3000 times brassinolide or 1000-1500 times seaweed extract.
2. Chemical Russeting
Chemical russeting appears as irregular streaks or patches composed of many small spots, which feel rough to the touch. It is mainly related to improper use of chemicals, such as low-quality emulsifiable concentrates, agricultural adhesives, metallic elements like potassium, sodium, and tin, precipitate-forming mancozeb, and certain organophosphate pesticides. Incorrect spraying techniques can also cause chemical russeting.
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Prevention Methods:
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Minimize the use of chemicals that are likely to cause russeting. Adhere to non-toxic control principles.
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Avoid holding the spray nozzle too close to the fruit surface while spraying.
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Control the concentration of the chemicals used to reduce the likelihood of chemical russeting.
3. Water Russeting
Continuous rainfall increases orchard humidity, and prolonged contact between the fruit surface and water can lead to severe water russeting.
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Prevention Methods:
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Ensure proper irrigation practices based on soil moisture and seasonal requirements.
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Adjust watering schedules according to drought and precipitation conditions.
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During the rainy season, focus on drainage to prevent waterlogging. Dig drainage ditches every three to four rows to ensure no water accumulation in the orchard.
In summary, russeting frequently occurs in apple cultivation and can easily be confused with other rust diseases, complicating prevention efforts. Therefore, it is crucial to enhance prevention measures, focusing on targeted management according to the different types of russeting.
AppleTree Management and Pest Control in June
