Citrus Leafminer Description

Figures 1 and 2. Examples of Citrus Leafminer Damage

The citrus leafminer (CLM) (Phyllocnistis citrella) is a Lepidoptera moth that has developed into one of the most destructive pests in the citrus industry. The citrus leafminer originated in Asia and is now found all over much of the citrus producing countries in the world. It was first discovered in the United States in southern Florida in 1993, and is now in every major citrus growing region in the lower 48. CLM made its first arrival in to California in 2000 in the Imperial Valley.

CLM damage is very noticeable as the larval feed and leave behind a maze of tunnels on the under and upper parts of the leaves. CLM larva are typically a light yellow color and typically leave a brown fecal trail inside the tunnels they mine. The larval have four instars that include 3 feeding instars and one non-feeding prepupa instar. The length of the larval stage is anywhere from 10-19 days. The larvae pupate by rolling the edge of a leaf over them and covering themselves with silk for protection.CLM adults are less than 2mm in length and have a wing span of about 4mm. They have off-white silvery forewings that have black and brown markings and a black spot on the end of each wing. The rear or hind wings are white with long scales protruding from the margins.

The CLM females lay eggs on new growth near the veins and midribs. Typical mating of the CLM occurs during the evening hours. This is mainly due to the adults emerging in the morning hours. The females typically lay the eggs on the underneath side of the leaves when the population densities are low. A typical female lays around 50 eggs in her lifetime, which hatch 4 to 10 days upon laying them. There can often be more than one leaf miner on a single leaf. It’s not uncommon to find 3 or more larval feeding on one leaf.