Aspen Leaf Miner

James Kruse, Forest Entomologist; 

Angie Ambourn, Biological Science 

Technician; and Ken Zogas, Biological Science 

Technician, USDA Forest Service, Alaska 

Region, State and Private Forestry.

Additional information on this insect can be 

obtained from your local Alaska Cooperative 

Extension office, Alaska State Forestry office, 

or from: 

Forest Health Protection 

State and Private Forestry 

USDA Forest Service 

2770 Sherwood Lane, Suite 2A 

Juneau, Alaska 99801-8545 

Phone: (907) 586-8883 

3301 “C” Street, Suite 522 

Anchorage, Alaska 99503 

Phone: (907) 743-9455 

3700 Airport Way 

Fairbanks, Alaska 99709 

Phone: (907) 451-2701 

www.fs.fed.us/r10/spf/fhp/fhpr10.htm

Aspen Leaf Miner

United States

Department of

Agriculture

Prepared by

Forest Service

Alaska Region

R10-PR-14

June 2007

Introduction 

The aspen leaf miner is a transcontinental 

pest of trembling or small tooth aspen. This 

species, Phyllocnistis populiella, is found across 

Alaska wherever poplar species are found. 

An outbreak of the aspen leaf miner has been 

occurring in Alaska since 2000. Acres of 

infested aspen identified during annual aerial 

surveys have increased from nearly 300,000 

acres in 2000, to more than 659,000 acres in 

2006. This is the second recorded outbreak 

exceeding 500,000 acres in Alaska (the first 

large recorded outbreak occurred during the 

late-1970s). Infestations of aspen leaf miner 

were noted along the Alaska Highway in 

Canada as early as the 1950s, and this insect 

also reaches outbreak proportions in the western United States. Outbreaks of aspen leaf 

miner rarely occur in eastern North America.

Life History

Adults are minute white moths with subtle 

brown or blackish markings on their lanceolate-shaped wings. Adults overwinter 

under the bark scales of both hardwood 

and conifer trees. Adults emerge, mate, and 

feed for approximately two weeks in early 

spring. Adults can often be seen resting on 

the sides of homes, windows, and cars. Flight 

begins before aspen trees break bud (see 

figure 1). Single eggs are deposited on the 

edge of newly emerged aspen leaves and the 

adult then folds the leaf edge over to form a 

protective shelter for the egg until the larvae 

hatch. Usually one or two eggs are laid per 

leaf when populations are low, but up to 

seven eggs per leaf have been found during 

outbreaks. When the new larvae hatch, they 

bore into the leaf and begin feeding between 

the epidermal tissues. Larvae are small, white, 

and very flat, reaching about 5 mm long. 

The larvae develop through four instars, and 

pupation occurs inside the mines. New adults 

emerge slightly before or during leaf senescence in late August and September. There is 

one generation per year.

Detection and Damage

Leaf mining damage is caused by the larval 

feeding or “mining” the leaf tissue, or mesophyll, between the upper and lower leaf 

surfaces. Host plants of the aspen leaf miner 

in Alaska include trembling aspen, balsam 

poplar, and occasionally willow and ornamental trees and shrubs in the genus Prunus. 

The aspen leaf miner causes a serpentine or 

Figure 1. Adult moth on aspen leaf bud.

Cover Photo. Aspen trees with silvery appearing foliage 

caused by the Aspen leaf miner.
CAUTION: Pesticides can be injurious to 

humans, domestic animals, desirable plants and fish, 

or other wildlife—if they are not handled or applied 

properly. Use all pesticides selectively and carefully. 

Since approved uses of a pesticide may change 

frequently, it is important to check the label for current approved and legal use. Follow recommended 

practices for the disposal of surplus pesticides and 

pesticide containers. Mention of a pesticide in this 

publication does not constitute a recommendation 

for use by the USDA, nor does it imply registration 

of a product under Federal Insecticide, Fungicide, 

and Rodenticide Act, as amended. Mention of a 

proprietary product does not constitute an endorsement by the USDA. 

sinuous mine that is typically confined to one 

side of the mid-rib. These mines give the leaf 

a silvery appearance (see cover photo). The 

majority of the feeding is done by late instar 

larvae and happens within a two week period. 

This feeding eventually causes the leaf to 

desiccate, turn brown, and drop prematurely. 

When looked at closely, leaf miner frass is 

Control Measures 

There are no effective control measures for 

large scale outbreaks of aspen leaf miner. 

As with many leaf mining insects, disease, 

parasitoids, and predators are the main causes 

for outbreak population crashes. Cannibalism 

can also occur if populations are so high that 

larval mines cross each other. It is also suspected that climate is influential in determining aspen leaf miner populations. Leaf mining 

insects tend to thrive in years associated with 

warm and dry weather. Thus, years with cold, 

wet weather may help lower populations of 

aspen leaf miner. 

Keeping trees in good health through fertilizing, watering, proper planting and pruning 

techniques, can help reduce the impacts of 

insect pests in general. Pruning may be effective for high value yard trees that are severely 

infested, as long as infected leaves and 

branches are removed or destroyed. Contact 

insecticides are not effective against leaf 

mining insects during their most damaging 

stage because they are protected inside the 

leaf. Some insecticides that are carried systemically through the tree can be effective in 

controlling leaf mining insects. Please contact 

your local Cooperative Extension office for 

more information and recommendations for 

insecticide treatments.

commonly observed in the hollowed out mine 

track leaving a thin black line in the center of 

the mine (see figure 2). Generally, the most 

obvious negative effect of this leaf mining 

is aesthetic. A reduction in tree growth due 

to reduced photosynthetic area, branch die 

back and top-kill are the suspected outcomes 

of sustained annual defoliation. Heavily 

damaged leaves have been shown to have 

lost up to 75 percent of their photosynthetic 

capability.

Figure 2. Mined aspen leaf. Note the serpentine mining 

and the frass—a thin black line in the mine.

Photos Credits:

Figure 1 by Patricia Doak, University of 

Alaska–Fairbanks.

Figure 2 by Ned Rozell, Anchorage Daily 

News science writer.

Cover photo Forest Service, Ken Zogas.

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