What are the latest causes of citrus re-greening?

During citrus production, a phenomenon called re-greening can occur, seriously affecting the appearance of the fruit, and both the sugar content and acidity of the fruit will decline, reducing fruit quality and affecting profits. So what causes citrus re-greening? Let's take a look at the detailed introduction below.

1. Excessive accumulation of nitrogen fertilizer

Applying too much nitrogen fertilizer during the growing period leads to excessive accumulation of nitrogen in the soil. Combined with rainy weather during the fruit ripening period, this can very easily cause the fruit to re-green. Therefore, when applying autumn shoot fertilizer, it is recommended to apply less slow-release fertilizer and instead choose quick-acting fertilizer as the shoot-promoting fertilizer. This can prevent fertilizer that has not been fully decomposed from releasing nitrogen during cloudy and rainy weather, thereby causing re-greening.

2. Weather temperature differences

During the color-change period of citrus, low temperatures can help the accumulation of sugars, anthocyanins and carotenoids in the fruit, thereby promoting fruit coloring. However, if warm weather returns during the color-change period, the peel, which has not yet fully matured, will regain the ability to synthesize chlorophyll, thus re-greening. Therefore, once cold air or warm currents appear during the color-change period, it will prolong coloring or cause re-greening, so preventive measures should be taken during the color-change period.

3. Too much quick-acting fertilizer

If too much quick-acting fertilizer or foliar fertilizer with high nitrogen content is sprayed during the color-change period of citrus, the excess nitrogen will combine with the ventilation within the fruit to form organic nitrogen. This will reduce the sugar content in the fruit, cause the branches and leaves of the plant to grow excessively, and compete with the fruit for ventilation, leading to a decrease in the sweetness of the citrus fruit. The content of anthocyanins and carotenoids in the peel will also decrease, and at this point re-greening is very likely to occur. Therefore, during the fruit color-change period, pay attention to the amount of fertilizer applied; do not apply too much quick-acting fertilizer, and also pay attention to nitrogen when spraying foliar fertilizer.

4. Poor tree vigor

For plantings with many fruits and few leaves, the nutrients synthesized through photosynthesis are limited, the tree vigor is poor, and the nutrients absorbed by the root system are also somewhat helpful. The fruit will then change color early and show signs of false ripening. When fertilizer is later applied to maintain nutrition, the fruit will show a brief re-greening phenomenon. Therefore, for plants with poor tree vigor, promptly thin flowers and fruits, control the number of fruits set, and at the same time strengthen nutrient supplementation during the flowering and fruiting period.

The above is an introduction to what causes citrus re-greening. We hope it can help you. If you want to learn more related knowledge, please stay tuned to us.