Entomology 462Ornamentals Pests:

Leafminers

David J. Shetlar, Ph.D.The “BugDoc”

The Ohio State University, OARDC & OSU Extension

Columbus, OH

© October, 2004, D.J. Shetlar, all rights reserved

Woody Ornamental Pest Groups

Chewing Pests - Leafminers

Woody Ornamental Pest Groups

Chewing Pests - Leafminers

Serpentine Leafminers - flies & caterpillars

Blotch Leafminers -beetles, sawflies, midges, caterpillars

Comma Leafminers -Agromyzid flies (pinholes)

Needleminers - caterpillars

The leafminers are a large and diverse group of insects that live, at least during their larval stage, between the upper and lower epidermal layers of host leaves. Most can be easily identified by their characteristic mines made in specific host plants.

Serpentine mines appear as winding trails that gradually get larger.

Blotch mines appear as oval, round, glove shaped, or irregular blotches on the leaf surface.

Comma mines are made by agromyzid flies. The mines start out as winding trails and end in a blotch.

Leafminers attacking conifers are called needleminers.

Serpentine leafminers simply make winding trails in leaves.

Solitary oak leafminer mines. This is a moth leafminer and the center white areas under the upper epidermis are cocoons.

Yellow poplar weevil adult on underside of deciduous magnolia, one of their favorite host plants.

Blotch mine of the yellow poplar weevil. Note it starts out as a linear mine until the larvae (which feed together) reach the leaf margin.

Birch leafminer female laying egg.

Extensive leafminer damage can leave a tree looking as if it has leaf scorch.

Birch leafminer larva in mine.

Spotted tentiform leafminer blotch mine on apple, upper surface left, lower surface right.

Spotted tentiform leafminer adult. Parasite larva after eating miner larva.

Pinholes are made by agromyzid (dipterous) leafminer adult females. They use their ovipositor to poke holes in host plant leaves for feeding.

Columbine leafminer adult, typical of an agromyzid leafminer.

Early columbine leafminer mines. They start out as serpentine mines but end up in a blotch mine.

Holly leafminer damage.Two holly leafminer pupae in mines and old pinholes.

Holly leafminer adult.

Spruce needle miner “nests.” Spruce needle miner adult.

Arborvitae leafminer damage. Each brown tip has been mined out by a larva.

Arborvitae leafminer adult.

Leafminer Control

Cultural –Resistant plantsPlant health care

Biological –Determine if present (parasites & predators)Conserve when possible

Chemical –Preventive-Adulticides: contact or stomach pesticides applied when

adult is active.Curative-Larvacides: use systemic pesticides, being aware of

translaminar and translocated activities.