What to do about abnormal fruit drop in citrus before harvest?

Citrus blooms, sets fruit, and ripens; just when it looks ready to pick, many citrus growers find that the citrus fruit has started to drop, and the losses from this are fairly serious. What exactly is the cause? The cause should lie in the tree itself. Let's take a look at the details together and learn how to prevent and improve this situation.

1. Causes

If the tree's nutrition is insufficient before harvest, very little nutrition is supplied to the fruit, and fruit drop occurs easily; in years and regions with high temperatures or sustained high temperatures, pre-harvest fruit drop occurs easily. After the fruit ripens, the stem end separates easily, so heavy rain can knock the fruit down, or the fruit absorbs too much water and drops; if light is poor, less nutritive material is produced, and nutritional deficiency fruit drop also occurs easily; drought and water loss in the later stage can cause fruit drop in large patches. Damage from pests and diseases also causes fruit drop.

2. Prevention

1. Nutrition

Apply sufficient fertilizer at every growth stage, and during the fruiting stage keep topdressing continuously until after harvest. Prune the canopy structure at any time to ensure good light penetration, satisfy photosynthesis, and ensure nutrition as much as possible, including the supply of essential trace elements in the soil.

2. Pruning

Prune excess branches; dead branches, branches crossing through the interior, drooping branches, and branches that disrupt the canopy must all be pruned away. This can save a large portion of nutrition. Prune at any time during the growing period, and the nutrition can be accumulated and supplied to the fruit.

3. Improvement

1. Weather

During high temperatures, spray water on the tree in the morning and evening to lower the temperature, or harvest the fruit early. Pay attention to weather effects; before heavy rain, dig ditches in advance for drainage to avoid waterlogging and allow rainwater to drain away promptly and smoothly. If there is drought, water the orchard every day from afternoon to evening to keep it moist, until it starts to rain and the weather eases.

2. Pests and diseases

A common disease is anthracnose; with anthracnose, a lesion often gradually expands and rots when it rains, and often half the fruit rots and then drops. If the lesion is on the leaf stalk, the fruit drops even more easily. Some fruits bored by insects, such as by fruit flies, look intact on the outside but are spoiled inside and drop on their own. Prevention is needed in advance, and timely control after occurrence.

When citrus seems about to ripen, fruit drop can still occur. The causes of this phenomenon are complex, and for various causes there are still some methods of prevention and improvement. But they may not be completely effective.