Leaf miners
Tiny larvae that tunnel inside leaves, leaving pale winding trails.
What you'll see
- Winding white or pale tunnels inside the leaves that widen as the larva grows.
- Blotchy, papery patches; badly mined leaves turn brown and drop.
- A tiny larva at the end of a tunnel when you hold the leaf up to the light.
Why it happens
The larvae of tiny flies, and of some moths and sawflies, feed between the upper and lower surface of the leaf.
How to fix it
- Pick off and bin mined leaves.
- On lightly mined leaves, squeeze the end of the tunnel to crush the larva inside.
- Keep plants watered and growing well so they outgrow light damage; sprays rarely reach larvae inside leaves.
Keep it from coming back
- Cover seedlings and leafy crops with fine mesh.
- Hold the leaves of new plants up to the light before buying.
- Avoid broad-spectrum sprays that kill the tiny wasps that keep leaf miners in check.
Sources
General guidance, not a diagnosis. For valuable, edible or outdoor crops, check with a local extension service or plant expert. Use any product exactly as its label says, and keep children and pets away while it dries.