citrus leaf miner

Symptoms

Silvery winding tunnels on young leaves, leaf curling.

Plants affected

• mandarin
• lemon tree

Easily confused with

• citrus canker

  How to tell them apart: Xanthomonas citri subsp. citri (citrus canker) produces raised, corky, tan-to-brown blister-like lesions on leaves, twigs and fruit, typically with a sunken centre and a bright yellow halo; lesions are firm, erupting and visible on BOTH leaf surfaces, and on fruit they form rough scabby pustules. Phyllocnistis citrella (citrus leafminer) leaves no corky pustules at all: instead its larva tunnels just under the leaf surface, creating a thin, silvery, serpentine 'snail-trail' mine with a dark central frass line, almost always on young flush leaves, which then curl and crinkle. If you see corky raised spots with yellow halos that feel rough, suspect canker; if you see a winding silver tunnel with a black thread inside the leaf, it is the harmless miner. Note canker often invades the margins of old miner trails, so check for the firm pustules specifically.

Common questions

How do I recognise citrus leaf miner on mandarin?

Silvery winding tunnels on young leaves, leaf curling.

Do I have to report citrus leaf miner?

No. citrus leaf miner is not a notifiable organism, so there is nothing to report to an authority. Treat it as a normal garden problem.

How is citrus leaf miner treated?

Mainly with biological and cultural measures — removing affected material, changing the conditions that favour it, and treating with agents approved in your country. The exact steps and their timing depend on the plant, the season and where you live: Dr. Phyto works them out in a free diagnosis.