What Causes Apple Fruit Drop
The editor explains the reasons for apple fruit drop in terms of horticultural knowledge. Keep reading to find out more!
What Causes Apple Fruit Drop
Apple fruit drop may be due to excessive tree vigor, which is fundamentally caused by improper fertilization. An imbalance between vegetative growth and reproductive growth can lead to mass fruit drop. It could also be caused by diseases and pests, such as rot disease, ring spot disease, and (T-J) disease, which can cause apple trees to drop their fruit. Measures to address these two causes include appropriate fertilization and pest control.
Reasons for Apple Fruit Drop
1. Natural fruit drop: Apple trees naturally drop fruit during the fruiting period. Generally, there are two peaks of fruit drop, the first about 10 days after flowering, and the second between July and August.2. Excessive tree vigor leading to natural fruit drop: Excessive tree vigor can also cause fruit drop, with the fundamental reason being improper fertilization.3. Fruit drop caused by diseases and pests: If dropped apples show signs of rot or if the tree trunk is rotting, consider whether the orchard is affected by diseases and pests, such as rot disease, ring spot disease, and (T-J) disease, all of which can cause apple trees to drop fruit. Fruit and flower drop due to physiological reasons are referred to as physiological fruit drop, which is caused by internal factors of the tree, not by natural disasters (or diseases and pests). Physiological fruit drop can be divided into early fruit drop and pre-harvest fruit drop. Like other pome fruits, apples typically have three peaks of early fruit drop. The first drop (i.e., flower drop) occurs shortly after flowering, when the ovary has not yet swelled. Another is when the flower bud is well-developed but fails to pollinate due to poor climatic conditions or limitations of the flower structure, both of which fail to achieve fertilization, causing the ovary to wither and drop due to a lack of hormones.What to Do if Apple Fruit Drop is Severe
Thinning flowers and fruit: Dense flowering can lead to poor tree nutrition and metabolic imbalance. If nutrition cannot keep up during the rapid fruit expansion or near maturity stages, it can cause mass fruit drop. Therefore, scientific and reasonable thinning of flowers and fruit is an effective measure to prevent fruit drop.Top-dressing under the tree: Based on the orchard's fertility and tree nutrition status, top-dress the trees with nitrogen, phosphorus, and potassium fertilizers 20-30 days before the physiological fruit drop. Adding a moderate amount of high-quality organic fertilizer can enhance the preventive effect.Foliar spraying: To quickly replenish tree nutrition and reduce fruit drop, foliar spray 2-3 times near the physiological fruit drop. To improve fruit quality, spray a 0.5% urea and 0.4% potassium dihydrogen phosphate solution.Spraying plant growth regulators: Before the physiological fruit drop, using plant growth regulators can effectively prevent fruit drop.Apple Fruit Drop Control Methods
Pulling branches to increase angles: Change the direction of upright apple branches by propping or pulling to disperse them, which can enhance ventilation and light penetration, inhibit excessive branch growth, and promote better growth during the fruit-setting period.Removing suckers and pinching: Severe pinching can effectively reduce nutrient consumption, allowing nutrients to accumulate in early shoots, thus accelerating young fruit growth and avoiding fruit drop due to insufficient nutrients.Reasonable fertilization: Do not promote tree vigor during the apple flowering and fruiting period. Gradually reduce nitrogen fertilizer and increase the amount of phosphorus and potassium fertilizers, and pay attention to watering to promote fruit expansion.Regular foliar fertilization: Spray amino acids, rare earths, or other trace fertilizers on the leaves every 7-10 days during the young fruit stage. Spraying should be detailed, uniform, and thorough. Foliar fertilization is effective but has limited efficacy and is only a supplementary measure, not a substitute for soil fertilization.Disease and pest control: If the apple tree trunk is rotting, consider using root soil irrigation or drenching with Yan Shang Ya, and applying Wan Jia Neng biological fertilizer. By supplementing probiotics, a probiotic environment can be formed, which significantly improves the control of various soil-borne diseases.This article shares the complete introduction to the causes of apple fruit drop, for everyone to learn and understand!