Leafminers tunnel through tissues within the leaf, this way they avoid chemicals and predators on the leaf surface. Most leafminers are maggots of the fly family Agromyzidae. Leafminer tunnels can be seen through the leaf surface, appearing pale green or white, with either linear, serpentine, or blotch-like shape. Most tunnels are found on the upperside of leaves and flowers, heavy infestation causing leaf wilting, drop and reduced crop yield. Indirect damage occurs when fungi or bacteria enter the feeding areas.
Infected leaves should be removed and disposed. Repel flies with reflectant material, trap them with yellow sticky tape. Biological control with Dacnusa sibirica and/or Diglyphus isaea wasps.