Causes of the second physiological fruit drop in citrus and how to prevent and control it

During the growth process of citrus, there are generally two physiological fruit drops each year, and this is also the main reason for normal citrus yield reduction. The second physiological fruit drop occurs in May-June, which is also the period of summer shoot sprouting and young fruit expansion. At this time, the fruit and shoots compete for nutrients, causing poor fruit growth and normal fruit drop. So what should be done about the second physiological fruit drop in citrus? Let's take a look at the detailed introduction below.

1. Control new shoots

During the summer shoot sprouting period, in order to avoid summer shoots sprouting and competing with fruit expansion for nutrients, the growth of summer shoots must be suppressed. For trees with relatively vigorous growth, the method of ring cutting to control shoots can be adopted, but for trees with relatively weak growth, ring cutting to control shoots is not suitable. Orchards with large-scale watering can adopt the method of manually removing summer shoots; for larger orchards, manual removal is time-consuming and labor-intensive, so it is recommended to use chemical shoot control. Spraying shoot-control agents before summer shoots sprout can reduce the amount of summer shoot sprouting.

2. Strengthen nutrition management

During the young fruit expansion period, both the young fruit and summer shoots need a large amount of nutrients for growth, and the main cause of the second physiological fruit drop is uneven nutrition. Therefore, if you want to prevent and control the second physiological fruit drop, the best method is to fertilize to supplement nutrients for the plant. Fertilization should be reasonably carried out according to factors such as tree vigor, soil, climate, and tree age. The fertilization principle is to apply less nitrogen fertilizer and more phosphorus and potassium fertilizer. This is to avoid excessive growth of summer shoots, so as not to worsen fruit drop. In addition, too much nitrogen fertilizer will affect the root system's absorption of other nutrients, while applying more phosphorus and potassium fertilizer can speed up nutrient transport, accelerate fruit expansion, and reduce fruit drop.

3. Pest and disease control

In addition to fruit drop caused by nutrition, pests and diseases are also one of the causes of fruit drop. In May-June, this is the period when citrus scale insects, whiteflies, and red spiders appear in concentrated numbers. They will harm leaves and fruit, reducing the nutrients synthesized by the leaves, so that the fruit does not have sufficient nutrients for growth, worsening fruit drop. Therefore, attention must be paid to the prevention and control of pests and diseases, focusing on prevention and integrated control, and spraying pesticides during the flowering and fruiting period to nip pests and diseases in the bud.

The above is an introduction to what to do about the second physiological fruit drop in citrus. We hope it can help you. To learn more related knowledge, please stay tuned to us.