Leaf Miners

If you have citrus trees, you have leaf miners.


Leaf miners can be found feeding on many edible and ornamental plants, including tomatoes, beans, cole crops, cucurbits, aster, peas, impatiens, petunia and dahlia. While leaf miners are generally not a threat to plant health, they can detract from a plant’s appearance and it is still a good idea to monitor infestations.

Tomato leaf with leaf miner damage (N3v3rl4nd) Public Domain

Leaf miners are not a specific insect. Instead, they are the larval stage of several moths, sawflies and some beetles. The damage is distinct burrows within leaves, leaving what looks like serpentine, white trails. By feeding within the leaf, leaf miners are protected from predators and pesticides. In fact, applying pesticides actually helps leaf miners by killing off their predators. To make matters worse, all leaf miner species are resistant to carbamates, pyrethroids and organophosphate pesticides.

Leaf miner damage on chard (Kate Russell)

Leaf miner on thumbnail (Kate Russell)

If you peel back the top layer of an infested leaf, you can actually see the pest, though you may need a magnifying glass.

You can minimize leaf miner damage by planting trap crops. Trap crops are preferred feeding plants. The most common trap crops are:

• lambsquarter
• velvetleaf
• columbine

Also, do not prune unnecessarily, as this stimulates new growth which is more susceptible.