🍃 Leafminer

How to identify

The adults are tiny yellow-and-black flies you'd barely notice, but the larvae are the artists: pale maggots that tunnel between the leaf's layers. The giveaway is winding, serpentine trails — pale squiggles that look like someone doodled on your leaf with whiteout.

Damage signs

Leaves develop winding white or brown tunnels that dry out and turn crispy along the trail. Heavy mining makes leaves look scorched, drop early, and robs the plant of photosynthetic real estate right when it needs it most.

Plants it attacks

Spinach, chard, beets, lettuce, tomatoes, peppers, beans, ornamentals

Non-chemical controls

• Pinch off and destroy mined leaves the moment you spot trails — the larva is inside the tunnel, so crushing or removing the leaf ends its commute.
• Hang yellow sticky traps just above the canopy; adult leafminer flies are drawn to yellow the way moths are drawn to a porch light.
• Release Diglyphus isaea, a parasitoid wasp so small you'd need a magnifier to admire it — females sting leafminer larvae and lay eggs on them.
• Cover young crops with floating row cover from day one to keep egg-laying adult flies off the plants entirely.
• Lay reflective silver mulch around plants — the flashing light disorients adults and cuts egg-laying dramatically.
• Rotate crops each season so leafminers pupating in the soil don't emerge to find their favorite host waiting in the same bed.