Most likely this is due to environmental conditions. to manage this issue, consider the following steps: Provide appropriate environmental conditions, including full sun, well-drained soil, and moderate watering. Fertilize your lemon tree regularly with a balanced fertilizer containing nitrogen, phosphorus, potassium, calcium, magnesium, and boron. Control pests and diseases through Integrated Pest Management (IPM) practices. Avoid overwatering or underwatering. Monitor tree health regularly and take prompt action against any signs of stress, pests, or diseases.