Guangzhou Fuerle Health Technology Co., Ltd , https://www.fuerlegroup.com
Apple trees need anti-sunburn during the rainy season
Sunburn disease, also known as sunscald, is a common issue affecting apple trees during hot and sunny periods. Affected apples show symptoms such as dehydration and scorching on the surface exposed to direct sunlight, resulting in reddish-brown, nearly circular spots. These spots gradually expand over time, eventually forming dark brown lesions surrounded by a yellowish halo. This condition significantly reduces the quality and market value of the apple crop. July and August are critical months for preventing sunburn, and effective measures should be taken to minimize its occurrence.
1. **Timely Irrigation**: Ensure that the orchard receives adequate water, especially during dry spells. Proper irrigation helps maintain tree health and reduces the risk of sunburn.
2. **Tree Trunk Mulching**: Before the onset of high temperatures and drought, apply a 20 cm thick layer of straw, grass, or wheat bran around the base of the tree. This not only protects the soil from overheating but also helps retain moisture, reducing the likelihood of sunburn.
3. **Fruit Covering**: For fruits that are most susceptible to sunburn, cover the sun-facing side with large leaves such as those from tung trees, ramie, or broadleaf grasses. This provides shade and reduces direct exposure to intense sunlight.
4. **White Paper Application**: Attach white paper to the sun-exposed side of vulnerable fruits. The reflective surface helps reduce heat absorption and prevents sunburn damage.
5. **Lime Milk Spraying**: Apply a thin layer of lime milk on the outer surface of the fruit. It reflects sunlight, helps prevent sunburn, and also has a mild antibacterial effect.
6. **Amino Acid Fertilizer Spraying**: From mid-June to late August, spray Meifeng or Qirui amino acid fertilizer at a dilution of 400 times, two to three times with a 15-day interval. This improves the tree’s drought resistance, reduces sunburn, promotes better fruit development, and enhances fruit quality. It also helps in forming strong flower buds for the following season.
7. **Evening Water Spraying**: During the evening or when the sun is low, spray the tree canopy with clean water. This helps cool down the foliage and reduces the risk of sunburn.
By implementing these strategies, growers can effectively manage sunburn disease and ensure healthier, more valuable apple crops. Regular monitoring and timely action are key to successful prevention.