What to do about abnormal fruit drop in citrus before harvest

Citrus blooms, sets fruit and ripens, and it looks like it is ready to be picked, but many citrus growers find that the fruit has started to drop, which causes fairly heavy losses. What exactly is the reason? The cause should lie in the tree itself. Let's look at the details together and learn how to prevent and improve this situation.

I. Causes

If the tree's nutrition is insufficient before harvest, very few nutrients are supplied to the fruit, making fruit drop very likely; in years and regions with high temperatures or sustained high temperatures, pre-harvest fruit drop is likely. 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 nutrients are produced, and nutrient-deficiency fruit drop is also likely; drought and water loss in the later stage can cause fruit drop over large areas. Pests and diseases also cause fruit drop.

II. Prevention

1. Nutrition

Apply sufficient fertilizer at every growth stage. During the fruiting period, keep topdressing continuously, all the way until after harvest. Prune the canopy structure at any time to ensure good light penetration, satisfy photosynthesis, and preserve nutrients as much as possible, including supplementing the trace essential elements in the soil.

2. Pruning

Prune excess branches. Dead branches, branches crossing through the interior, drooping branches and branches that disrupt the canopy structure must all be pruned away. This can save a large portion of nutrients. Prune at any time during the growing period, so nutrients can be stored and supplied to the fruit.

III. Improvement

1. Weather

In high temperatures, you can 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 drainage ditches in advance 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 moderates.

2. Pests and diseases

A common disease is anthracnose. With anthracnose, a lesion often gradually expands, rots when it rains, and often half the fruit rots before it drops; if the lesion is at the leaf stalk, the fruit drops even more easily. Some fruits are bored into by insects, such as fruit flies; the outside looks intact, but the inside is spoiled, and the fruit drops on its own. Prevention is needed in advance, and timely control after it occurs.

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