The Amber-Marked Leaf Miner The amber-marked birch leaf miner Ed Holsten, Research Entomologist, Revised by United States Department of Agriculture thomsoni (Konow) James Kruse, Forest Entomologist and Nicholas The amber-marked birch leaf miner (AMBLM) Lisuzzo Biological Science Technician,USDA Forest Service, Alaska Region, State and Private Forestry. is believed to have been introduced from Europe into the northeastern United States Additional information on this can be The Amber-Marked in the early 1900s. Since then, it has become obtained from your local Alaska Cooperative established throughout many parts of Canada, Extension office, Alaska State Forestry office, or and was first reported in Edmonton, Alberta in from: Birch Leaf Miner the early 1970s. Forest Health Protection The first specimens of AMBLM in Alaska were State and Private Forestry USDA Forest Service recorded in Haines in 1991. By 1996, the 3700 Airport Way AMBLM was reported in Anchorage. Intense Fairbanks, Alaska 99709 outbreaks with noticeable defoliation were Phone: (907) 374-3758 a yearly occurrence in the Anchorage Bowl and, to some degree, in the Mat-Su Valley, for Forest Health Protection approximately a decade after introduction. State and Private Forestry USDA Forest Service The AMBLM was detected in Fairbanks in 2002, 161 East 1st Avenue where the population of the insect appears to Anchorage, Alaska 99501 be growing. Hardest hit have been urban birch Phone: (907) 743-9453 trees; until recently damaged trees in natural settings have not been observed. Forest Health Protection State and Private Forestry This brochure describes the life history USDA Forest Service and life stages of the AMBLM and presents 11175 Auke Lake Way homeowners with guidelines for minimizing Juneau, Alaska 99801 damage to ornamental and native birch. Phone: (907) 586-8883 http://www.fs.fed.us/r10/spf/fhp Life History: The U.S. Department of Agriculture (USDA) Amber-marked birch leaf miners spend prohibits discrimination in all its programs and the winter in the prepupal stage in the soil activities on the basis of race, color, national beneath defoliated birch. Pupation occurs in origin, sex, religion, age, disability, political the summer and the adults (almost always beliefs, sexual orientation, or marital or family females) emerge in June and July depending status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require upon temperature and humidity. Adult alternative means for communication of program emergence may last for more than a month. information (Braille, large print, audiotape, etc.) Eggs are deposited singly in slits cut in young should contact USDA’s TARGET Center at (202) leaves, and males are not needed for females 720-2600 (voice and TDD). to reproduce. Larvae feed on the tissues To file a complaint of discrimination, write USDA, between the leaf surfaces. Young larvae feed Director, Office of Civil Rights, Room 326-W, singly (Figure 1). As the individual larval mines Whitten Building, 1400 Independence Avenue, increase in size, they coalesce and form large, SW, Washington, DC 20250-9410, or call (202) Forest Service R10-TP-159 hollowed-out brown areas in the leaf. As many 720-5964 (voice and TDD). USDA is an equal Alaska Region July 2014 opportunity provider and employer. as 20–40 larvae may be found feeding in one leaf. Mature larvae chew their way out of the in urban areas. In order to avoid moisture leaf and drop to the ground. They enter the stress, adequate water should be provided to litter layer and form small earthen cells, 2.5 the trees, at least once a week, throughout to 5 cm below the soil surface. There they the growing season. Spring fertilization also spin browb papery cocoons. There is one helps to promote tree vigor and to minimize generation of AMBLM per year. the effect that defoliators such as leaf miners Description: might have on a tree. The University of Alaska Cooperative Extension Service should be Mature larvae are somewhat flattened, consulted for specific information on the type yellowish white, and are about 6 mm long. and amount of fertilizer or pesticide to be Adults are black and about 3 mm long. Adult applied. populations are comprised of females. In 2006 a biological control project was Guidelines for Reducing Damage: initiated involving the USDA Forest Service, The most obvious sign of infestation is severe the Alaska Division of Forestry, the and browning and distortion of foliage beginning in Plant Health Inspection Service (APHIS) and July and August. Damage appears to be more the University of Massachusetts-Amherst. serious on open-grown ornamental birch than From 2006 through 2011 they released a on birch in forest stands. However large stands species of wasp that attacks the AMBLM of affected forest have been recently reported larvae in numerous locations around the on the Kenai Penisula. Defoliation of birch Anchorage Bowl and the Fairbanks area. The introduced wasps in combination with native wasps found attacking AMBLM and poor weather conditions appear to have reduced populations and damage in the Anchorage area. In 2007, a similar release of introduced wasps was made on Eielson Airforce Base, and Figure 2. By late summer outbreaks of amber in 2011 in Fairbanks, AK. marked birch leaf miner can turn the entire foliage of a tree brown, such as the tree CAUTION: Pesticides can be injurious pictured above. to humans, domestic , desirable plants, and fish or other wildlife, if they are trees in the Fairbanks area has also increased not handled or applied properly. Use all dramatically since 2011. Heavily defoliated pesticides selectively and carefully. Since trees may be more susceptible to attack by approved uses of a pesticide may change other and pathogens. Tree mortality as frequently, it is important to check the label a result of birch leaf miner defoliation has not for current approved and legal use. Follow been observed in Alaska. recommended practices for the disposal of It is important to that birch growing in urban surplus pesticides and pesticide containers. settings have the best possible conditions. Mention of a pesticide in this publication does Care should be taken to avoid injuring the not constitute a recommendation for use by Figure 1. A birch leaf with six amber marked roots, either mechanically or through soil birch leaf miner larvae begining to feed on the USDA, nor does it imply registration of a the leaf tissue. Their feeding creates small compaction. Soil should neither be placed on product under Federal Insecticide, Fungicide, mines, which turn into brown “blotches” on top of nor removed from the area beneath and Rodenticide Act, as amended. Mention of the leaf surface. the crown of the tree. are very a proprietary product does not constitute an susceptible to drought conditions, especially endorsement by the USDA.