Solution: targeted supplementation of yellow flowers or iron-containing fertilizers.
2. Malnutrition causes the leaves of lemon trees to turn yellow. After flowering, the leaves turn yellow and fall off
Solution: Malnutrition leads to yellowing of leaves, and potassium dihydrogen phosphate can be sprayed. This fertilizer contains a lot of trace elements besides nitrogen, phosphorus and potassium.
3. Root rot causes the leaves of lemon trees to turn yellow. For example, there will be bark rot and the smell of distiller's grains.
Solution: Root rot is often caused by too much water in the basin or too much fertilization. The diseased part and a small amount of healthy tissue can be scraped clean with a sharp knife, and 65,438+000 times of red copper and 200~300 times of topaz are applied to the scraped mouth, and the wound can be covered with soil after healing.
Insect pests can cause the leaves of lemon trees to turn yellow, which is usually visible to the naked eye.
Solution: Manually exterminate insects or spray corresponding chemicals.
Extended data:
Lemons are like fertilizer. Usually, more thin fertilizer should be applied. Apply decomposed liquid fertilizer once before plants germinate, and then apply liquid fertilizer with nitrogen as the main fertilizer every 7~ 10 days to promote more branches and leaves and more spring shoots. After the lemon blooms, in addition to applying thin fertilizer once a week, the flowers and fruits must be thinned. Sparse some buds before flowering; After flowering and fruit setting, in order to reduce nutrient consumption, some young fruits with improper positions should be thinned.
In the process of fruit growth, if the fertilizer and water are sufficient and the plants are nutritious, some branches will sprout new buds, and the growth of new buds will inevitably divert some nutrients, which will affect the growth of fruits. In order to protect the fruit, the new buds should be smoothed in time.