WSU Extension

Hortsense

Common Insects & Mites : Leafminers
(revision date: 4/30/2013)


Biology
Leafminers are common on many plants; however, they are fairly host-specific. If you know the plant species where a leafminer is feeding, you can name the leafminer based on the plant species (e.g., madrone leafminer, lilac leafminer, and so on). Leafminers feed on the green tissues between the leaf surfaces and create mines or blotches on the leaf. The two most common types are serpentine leafminers and blotch leafminers. Serpentine leafminers produce a narrow, winding trail of mined tissue. Blotch leafminers leave a large damaged spot with an irregular outline. In both cases the upper and lower epidermis of the leaf is left behind and shelters the feeding larva. The epidermal layers often become whitish, tan, or brown and may appear papery and dry.
Management Options

Non-Chemical Management
  • Natural predators may help control populations. Encourage predators such as green lacewings and spiders.
  • Pinch, or pick and destroy, infested leaves to kill larvae.
Select non-chemical management options as your first choice!

Chemical Management

None recommended.

Images
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Caption: Rose leafminer damage
Photo by: A.L. Antonelli
Caption: Madrone leafminer and shieldbearer damage
Photo by: S.J. Collman
Caption: Rhododendron leafminer damage
Photo by: A.L. Antonelli
Caption: Goldenchain leafminer damage
Photo by: A.L. Antonelli
Caption: Apple tentiform leafminer damage
Photo by: J.F. Brunner