Aspen Leaf Miner Introduction James Kruse, Forest Entomologist; Aspen Leaf Miner The aspen leaf miner is a transcontinental Angie Ambourn, Biological Science pest of trembling or small tooth aspen. This Technician; and Ken Zogas, Biological Science species, Phyllocnistis populiella, is found across Technician, USDA Forest Service, Alaska Alaska wherever poplar species are found. Region, State and Private Forestry. An outbreak of the aspen leaf miner has been Additional information on this insect can be occurring in Alaska since 2000. Acres of obtained from your local Alaska Cooperative infested aspen identified during annual aerial Extension office, Alaska State Forestry office, surveys have increased from nearly 300,000 or from: acres in 2000, to more than 659,000 acres in 2006. This is the second recorded outbreak Forest Health Protection exceeding 500,000 acres in Alaska (the first State and Private Forestry large recorded outbreak occurred during the Figure 1. Adult moth on aspen leaf bud. USDA Forest Service late-1970s). Infestations of aspen leaf miner 2770 Sherwood Lane, Suite 2A were noted along the Alaska Highway in Juneau, Alaska 99801-8545 Canada as early as the 1950s, and this insect seven eggs per leaf have been found during Phone: (907) 586-8883 also reaches outbreak proportions in the west- outbreaks. When the new larvae hatch, they 3301 “C” Street, Suite 522 ern United States. Outbreaks of aspen leaf bore into the leaf and begin feeding between Anchorage, Alaska 99503 miner rarely occur in eastern North America. the epidermal tissues. Larvae are small, white, Phone: (907) 743-9455 and very flat, reaching about 5 mm long. Life History The larvae develop through four instars, and 3700 Airport Way pupation occurs inside the mines. New adults Adults are minute white moths with subtle Fairbanks, Alaska 99709 emerge slightly before or during leaf senes- brown or blackish markings on their lan- Phone: (907) 451-2701 cence in late August and September. There is ceolate-shaped wings. Adults overwinter one generation per year. www.fs.fed.us/r10/spf/fhp/fhpr10.htm under the bark scales of both hardwood and conifer trees. Adults emerge, mate, and feed for approximately two weeks in early Detection and Damage Cover Photo. Aspen trees with silvery appearing foliage spring. Adults can often be seen resting on Leaf mining damage is caused by the larval caused by the Aspen leaf miner. the sides of homes, windows, and cars. Flight feeding or “mining” the leaf tissue, or meso- begins before aspen trees break bud (see phyll, between the upper and lower leaf figure 1). Single eggs are deposited on the surfaces. Host plants of the aspen leaf miner edge of newly emerged aspen leaves and the in Alaska include trembling aspen, balsam adult then folds the leaf edge over to form a poplar, and occasionally willow and orna- protective shelter for the egg until the larvae mental trees and shrubs in the genus Prunus. United States Prepared by R10-PR-14 hatch. Usually one or two eggs are laid per The aspen leaf miner causes a serpentine or Department of Forest Service June 2007 leaf when populations are low, but up to Agriculture Alaska Region sinuous mine that is typically confined to one Control Measures Photos Credits: side of the mid-rib. These mines give the leaf There are no effective control measures for Figure 1 by Patricia Doak, University of a silvery appearance (see cover photo). The large scale outbreaks of aspen leaf miner. Alaska–Fairbanks. majority of the feeding is done by late instar As with many leaf mining insects, disease, Figure 2 by Ned Rozell, Anchorage Daily larvae and happens within a two week period. parasitoids, and predators are the main causes News science writer. This feeding eventually causes the leaf to for outbreak population crashes. Cannibalism Cover photo Forest Service, Ken Zogas. desiccate, turn brown, and drop prematurely. can also occur if populations are so high that When looked at closely, leaf miner frass is larval mines cross each other. It is also sus- pected that climate is influential in determin- ing 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 fertil- izing, watering, proper planting and pruning techniques, can help reduce the impacts of insect pests in general. Pruning may be effec- tive 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 Figure 2. Mined aspen leaf. Note the serpentine mining The U.S. Department of Agriculture (USDA) prohibits and the frass—a thin black line in the mine. mining insects during their most damaging discrimination in all its programs and activities on the stage because they are protected inside the CAUTION: Pesticides can be injurious to basis of race, color, national origin, age, disability, and leaf. Some insecticides that are carried sys- humans, domestic animals, desirable plants and fish, where applicable, sex, marital status, familial status, or other wildlife—if they are not handled or applied parental status, religion, sexual orientation, genetic commonly observed in the hollowed out mine temically through the tree can be effective in properly. Use all pesticides selectively and carefully. information, political beliefs, reprisal, or because all track leaving a thin black line in the center of controlling leaf mining insects. Please contact Since approved uses of a pesticide may change or part of an individual’s income is derived from any the mine (see figure 2). Generally, the most your local Cooperative Extension office for frequently, it is important to check the label for cur- public assistance program. (Not all prohibited bases obvious negative effect of this leaf mining more information and recommendations for rent approved and legal use. Follow recommended apply to all programs.) Persons with disabilities who require alternative means for communication of pro- is aesthetic. A reduction in tree growth due insecticide treatments. practices for the disposal of surplus pesticides and pesticide containers. Mention of a pesticide in this gram information (Braille, large print, audiotape, etc.) to reduced photosynthetic area, branch die publication does not constitute a recommendation should contact USDA’s TARGET Center at (202) 720- back and top-kill are the suspected outcomes for use by the USDA, nor does it imply registration 2600 (voice and TDD). To file a complaint of discrimi- nation, write to USDA, Director, Office of Civil Rights, of sustained annual defoliation. Heavily of a product under Federal Insecticide, Fungicide, and Rodenticide Act, as amended. Mention of a 1400 Independence Avenue, S.W., Washington, D.C. damaged leaves have been shown to have 20250-9410, or call (800) 795-3272 (voice) or (202) proprietary product does not constitute an endorse- 720-6382 (TDD). USDA is an equal opportunity pro- lost up to 75 percent of their photosynthetic ment by the USDA. capability. vider and employer..