After citrus blossoms, the speed at which fruitlets turn green is one of the criteria for measuring the quality of fruit setting. However, sometimes citrus fruitlets not only turn green slowly but also turn yellow. So, what are the specific reasons for this? Let's understand together.
Reasons for Citrus Fruitlets Turning Yellow
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Insufficient Nutrients: When the tree is overly vigorous, with too many shoots and few flowers, the fruits are easily deprived of nutrients. If the tree focuses on vegetative growth, the fruitlets may turn yellow and fall due to insufficient nutrients.
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Immature Spring Shoots: If spring shoots are not mature, meaning they have not become functional leaves, they cannot produce organic matter. Instead, they compete with fruitlets for nutrients, leading to insufficient nutrition for the fruitlets and failure to turn green.
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Improper Girdling: Blind or premature girdling can cause sudden nutrient interruption in the tree, depriving new leaves and developing fruitlets of necessary nutrients, resulting in delayed greening and yellowing and shedding of fruitlets.
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Improper Hormone Use: Excessive hormone concentration beyond the fruitlets' tolerance threshold can also lead to yellowing of the fruitlets.
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Environmental Factors: Environmental factors such as light, rainfall, etc., can also affect citrus fruitlet color. Insufficient or excessive light and water can easily cause citrus fruitlets to turn yellow.
Solutions to Citrus Fruitlets Turning Yellow
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Proper Fertilization: For trees with insufficient nutrients, proper application of nitrogen-containing fertilizers to maintain nutrient balance is key to solving citrus fruitlet yellowing. Quick nutrient supplementation can be achieved by foliar spraying with 600-800 times dilution of Agrotop, combined with exogenous hormones like 920, cytokinins, etc., to regulate nutrient balance and accelerate fruitlet greening.
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Plant Management: Strengthen plant management, especially for trees with excessive shoots or few flowers. To avoid competition with fruitlets for nutrients, timely pruning of shoots and branches, as well as removal of weak or deformed flowers, helps to stabilize fruit setting.
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Scientific Pesticide Use: When using hormone pesticides or other pesticides, pay attention to proper dosage and application methods. Rotate pesticides regularly and ensure thorough and even spraying without dripping onto branches and leaves.
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Environmental Regulation: Prune branches obstructing light to increase illumination; maintain appropriate watering to avoid under or overwatering. Drainage should be strengthened during cloudy and rainy weather.
In conclusion, while there are various reasons for citrus fruitlet yellowing, solving it is not difficult. The key lies in properly replenishing nutrients, fertilizing after each harvest and blossom, and restoring tree vigor. For vigorously growing trees, attention should be paid to pruning, shoot thinning, flower thinning, etc., to implement fruit retention measures, effectively preventing citrus fruitlet yellowing.
