Aspen Blotch Leafminer: Appearance, Territory, Damage and Life Cycle

Latin Name: Phyllonorycter Tremuloides

Appearance: The leaf blotch miner moth Aspen Blotch Leaf Miner belongs to the Lepidoptera family. The aspen blotch miner feeds under the leaves of three host tree species in north-central Minnesota, USA. Adults have thin bronzy brown forewings with five, occasionally four, typically oblique white costal lines and five, somewhat variable, white dorsal bands. The hindwing and fringe are of a light gray color. Eggs are flat and faintly glued to the host leaf.

Hosts Plants: Aspen Plants

Territory: North America’s range extends from New Mexico, Ohio, and southern Maryland north to central Alaska and Ontario.

Damage Insect Cause: This insect’s adults are small moths. Early instar larvae are flat and mine within the host’s leaves. The larvae excrete blotched mines, which may be more noticeable on one side of the leaf than the other. Miners weave silk over the surface of the leaf, which dries and shrinks to form a ridge above the mine. During the summer, the larvae feed on tissue inside the leaves after initially feeding on sap.  When possible, remove affected leaves from smaller plants. Aspen and cottonwood trees are particularly vulnerable. Plant blotch miner-resistant tree cultivars in locations with heavy blotch miner infestations.

Life History and Habits: The life cycle is same as other leaf miners. The leafminer has four phases of development: egg, larva, pupa, and adult moth. Adults do not harm plants and have a lifespan of 1 to 2 weeks. The eggs hatch approximately a week after they are deposited. The freshly born larvae immediately begin eating in the leaf, producing small, practically undetectable mines at first. Each year, there may be more than one generation.