WSU Extension


Beet, Chard : Beet or spinach leafminer
(revision date: 6/2/2014)

The beet or spinach leafminer is the larva of a small (1/4") gray fly with black hairs. Eggs are laid on the leaves of beets, chard, spinach, and weeds including lambsquarters. The emerging maggots mine between the upper and lower surfaces of the leaf, forming narrow mines which later enlarge into pale blotches. Damaged leaves are distorted. The white larvae are about 1/4" long when mature. They emerge from the leaves and pupate in the soil.
Management Options

Non-Chemical Management
  • Control weeds in and around the garden.
  • Rotate crops. Do not replant where crops were infested the previous year.
  • Pinch leaves to kill larvae inside.
  • Pick out infested leaves when noticed. Discard leaves in garbage.
  • Screen plants with a floating row cover prior to emergence of flies in spring (April-May).
Select non-chemical management options as your first choice!

Chemical Management

None recommended

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Caption: Spinach leafminer damage
Photo by: A.L. Antonelli