Below are the most common causes of curling citrus, along with ways to manage them:
- Water stress
- Or all of the above
Drought stress is the most common cause of leaf curl in citrus, but is also the easiest to remedy. If leaves begin to curl inward while retaining their green coloration and the soil around your tree feels dry to the touch, you’re not watering enough. Stepping up watering efforts and applying 2 to 4 inches (8 cm.) of an organic mulch to the ground around your citrus plant will help it recover. Wait to fertilize until the tree resumes normal, healthy leaf production.
Check for evidence on the underside of the leaves. Spray your citrus tree with insecticidal soap or neem oil or a good insecticide. Repeat until the plant begins to recover.
Silvery lines or trail on the new leaves means your tree has citrus leafminer. It’s a tiny moth that lays its eggs on the leaf. The hatched larvae tunnel into the leaf and cause the tunnels creating ugly distorted leaves, reducing the harvest on the trees. Spray the plant with Pest Oil or Eco Oil every two weeks ensuring to spray both the top and bottom of the leaves.
It shows up in citrus as leaves with a yellow cast that are bent downward at the tip. Check the soil pH and nutrient levels before fertilizing these trees to ensure there aren’t bigger problems.
If everything checks out, supplement with an extra dose of fertilizer and monitor your tree for improvement. Make sure to provide the tree with enough water to move potassium throughout its system.
Citrus leaves may curl in response to cold weather. Many types of citrus withstand overnight frost or short periods of frost. Blossoms and fruit of most citrus are sensitive to frost. Dead leaves that still attached at the tops of trees and outer canopies after periods of cold weather may indicate frost damage. Cover canopies with cloth or plastic sheets overnight to protect them from mild frost.
Most types of citrus trees recover well after minor frost damage.