Why do the leaves on a citrus tree curl?

There are three things that make leaves on a citrus tree curl, including insect infestation, overwatering and change of climate. Insects such as the citrus leaf miner lay eggs on citrus tree leaves, and the larvae feed on the leaves.

Other insects that feed on citrus tree fruits include mites and aphids. These insects suck juices from the leaves effecting the growth of the leaves. Overwatering also causes the leaves to curl. Curling of citrus trees leaves can also be caused by cold climate. However, this can be reversed under warmer conditions. Appropriate insecticides are used to address the problem of leaves curling on citrus trees.