tv Biology, Ecology, and Control Dfthe -ODGEPOLE NEEDLE MINER SERVE .S. DEPARTMENT OF AGRICULTURE • FOREST SER VICE • T ECHN I C AL BULLETIN NO. 1458 'f 'CS^*»* I Î ^..jii ■■-3. ä'^i *-?»».î ^m >. 388925 LIBRARY ABSTRACT Struble, George R. 1972. Biology, ecology, and control of the lodgepole needle miner. USDA Tech. Bull. 1458. 38 p., illus. The lodgepole needle miner attacks lodgepole pine forests in the Western United States and Canada. Only two insect species— Coleotechnites milleri (Busck) and C. st(Mrki Freeman—have been identified and studied in detail. Infestations by C. milleri were studied at Yosemite National Park, California, beginning in 1954. This bulletin summarizes findings on the biology and ecology of this species, natural enemies and pathogens, effects of climate and physio- graphy, and field tests of insecticides. Keywords: Defoliators, insect, Coleotechnites milleri (Busck), natural control, aerial spray, lodgepole pine. F521661 Cover Photo Defoliated lodgepole pines stand as mute evidence of a devastating infestation by the lodgepole needle miner. These trees, on the Tenaya Creek drainage, Yosemite National Park, California, were killed between 1910 and 1925. Issued October 1972 Issued February 1973 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402—Price 30 cents Stock Number 0100-2596 263íf69 CONTENTS Page ACKNOWLEDGMENTS ü SUMMARY iii INTRODUCTION 1 HOSTS AND DISTRIBUTION 3 Lodgepole Pine 3 Associated Host Trees _ _ 4 LIFE CYCLE 4 LIFE STAGES 5 Adults 5 Eggs 5 Larvae 5 Pupae 8 BIOLOGY 8 Emergence and Sex Ratio 8 Flight 8 Mating and Oviposition 9 Incubation and Eclosión 10 Larval Development 10 Pupal Period 13 EFFECT ON HOST TREES 13 Foliage Loss and Regrowth 13 Stem and Sfioot Growth Decline 14 Tree Injury and Mortality 15 STUDIES OF INFESTATIONS 15 Sampling Procedures 16 Zone Limitations 18 NATURAL CONTROL 19 Arthropod Enemies 19 Birds , 25 Pathogens 26 Weather 26 INSECTICIDAL CONTROL 30 Effect on Needle Miners _ _ _ 32 Effect on Nontarget Organisms 34 CONCLUSIONS 35 LITERATURE CITED 36 ACKNOWLEDGMENTS This bulletin summarizes stud- periment Station, for his capable ies begun in 1954 and conducted leadership, direction, and support. in Yosemite National Park, Cali- Other entomologists and research- fornia, by the California (now ers who took part, and whose ef- Pacific Southwest) Forest and forts are deeply appreciated, in- Range Experiment Station, For- clude George L. Downing, Ralph est Service, U.S. Department of C. Hall, Robert L. Lyon, Arthur Agriculture, in cooperation with D. Moore, Robert E. Stevens, the National Park Service, U.S. Richard H. Smith, Boyd E. Wick- Department of Interior. Research man, and Thomas W. Koerber planning and experimentation from the Pacific Southwest Forest were facilitated through a coop- and Range Experiment Station; erative agreement drawn up be- Clarence G. Thompson and Mauro tween Yosemite National Park E. Martignoni from the Pacific and the Experiment Station. The Northwest Forest and Range Ex- Park provided field laboratories, periment Station; A. D. Telford quarters, equipment, and person- from the University of California, nel. Berkeley; and identification tax- Special credit should be given onomists from the Agricultural to Charles B. Eaton, Pacific Research Service, U.S. Depart- Southwest Forest and Range Ex- ment of Agriculture. SUMMARY The lodgepole needle miner at- fourth overwinter, and the fifth tacks and kills indigenous lodge- pupates beginning about the pole pine forests in the Western third week of June. United States and Canada. Only After eclosión, larvae enter two species—Coleotechnites mil- and remain within the first nee- leri (Busck) and C. starki Free- dle through the third instar; man—have been identified and they migrate to and mine two ad- studied in detail. C. milleri is ditional needles each in the best known for long periods of fourth and fifth instar. A mini- outbreaks in Yosemite and Se- mum of five needles are mined, quoia-Kings Canyon National and entries are made into many Parks in California. Three pe- others by time of pupation. riods of infestation have been re- Extreme populations of 75 or ported since 1900. Each lasted 10 more insects per twig tip mark to 20 years and was followed by the beginning of new infestations ; a shorter period of light infesta- 30 insects per tip are usual tion in between. Infestations by through the third generation. C. starki are well known in the Afterward, the stress of defolia- Banff and Lake Louise National tion and growth of shorter and Parks in the Canadian Rocky fewer needles result in lower Mountains. Scattered infesta- populations. Populations are tions of unidentified needle miner larger and more uniform in the species have been found in and tops and midcrowns of trees. near Yosemite National Park Possible insect enemies of the and on the Inyo National Forest lodgepole needle miner include in California; in Yellowstone 57 species in five orders. None National Park, Wyoming; and in has been found highly effective central Oregon. against outbreak infestations. This bulletin summarizes find- Sharp reductions in outbreak ings from studies conducted in infestations followed adverse Yosemite National Park on the weather during flight and ovipo- biology and ecology of C. millerij sition. its natural enemies and patho- Control by toxic chemical gens, relationship of climatic and sprays applied by helicopter has been undertaken in Yosemite Na- physiographic influences to suc- tional Park as a stopgap measure cessive generations of needle to save recreational forests from miners, and field tests of insecti- devastation. Malathion proved cides. the most effective. Moths were The life cycle of C. milleri sprayed by helicopter at the rate spans 2 years. Moths oviposit be- of 1 pound malathion in 10 gal- tween July 15 and August 20 lons diesel oil per acre. The every odd-numbered year in Yo- sprays caused infestations to semite. Mean incubation period of drop and remain at innocuous eggs lasts 35 days. Overlapping levels. Nontarget organisms did generations are unknown. Of the not suffer any evident lasting five larval instars, the first and damage. Ill TÍJW, j- i: a> l-f / BIOLOGY, ECOLOGY, AND CONTROL OF THE LODGEPOLE NEEDLE MlNER^^r u 3 By Gearge R. Struble ' INTRODUCTION On the upper slopes of Califor- and studied in detail. C. milleri is nia's central Sierra Nevada most notorious for long periods stand dead forests of lodgepole of outbreaks in the upper Tuol- -pine ñiPinus contorta -¥ar: mu^ umne-Merced River watersheds rayana} [Grev. & Balf.] En- in Yosemite National Park, Cali- gelm.). The snags contrast fornia (Patterson 1921; Struble vividly with nearby living trees. 1958; Yuill 1942). Lesser infes- Many thousands of trees stripped tations have occurred 125 miles of their foliage foretell a similar to the south in the upper Kings- fate for others in the years Kern watersheds of the Sequoia ahead. Some of these "ghost for- and Kings Canyon National est" trees have stood for more Parks. Epidemic outbreaks of C. than 60 years, but many trees starki have been recorded in have fallen into crisscross entan- Banff and Lake Louise National glements. Parks in the Rocky Mountains of The cause of this devastation Canada (Stark 1959). Though is the larvae of a tiny moth—^the highly destructive, these out- lodgepole needle miner. Several breaks persist for shorter pe- species of the insect attack lodge- riods than those of C. milleri. pole pine foliage. All belong Three periods of major infes- to the genus Coleotechnites tations by C milleri have been (Hodges 1965) = Evagora (Free- reported since 1900. The first man 1960) = Recurvaría (Lepi- began about 1903 and subsided doptera: Gelechiidae). They are after 1921; the second extended found in parts of California, Ore- from 1933 to 1941 ; and the third gon, Idaho, Utah, and Wyoming lasted from about 1947 to 1963 in the Western United States ; and (fig. 1). in Alberta, Canada. The 2-year life cycle of C, mil- To date, only two species—C. leri begins in the odd-numbered milleri (Busck) and C. starki year and that of C starki in the Freeman—have been identified even-numbered year. C. milleri causes far more damage to nee- * Research Entomologist, Pacific dles initially, in subsequent gen- Southwest Forest and Range Experi- erations, and for longer periods ment Station, Forest Service, U.S. De- partment of Agriculture, Berkeley, than does C. starki. Sustained California. higher populations and more F521080—F521081—F521082—F521083 Figure 1.—A, Dead forest, killed about 1906; B, infested, pole-size trees among snag remanants in 1953; C, dying, mature forest in 1963, heavily infested since 1953; D, twig tips with reduced complements of shortened foliage. feeding per larva contribute to milleri, the Pacific Southwest this difference between the two (then California) Forest and species. Range Experiment Station Another species of Coleotechn- joined forces with the U.S. Na- ites, closely related to C. milleri, tional Park Service in coopera- has been observed infesting lodge- tive studies at Yosemite National pole pine in the Inyo National Park, starting in 1954. Forest, Mono County, California This report summarizes find- (Struble 1968). This species is ings from these studies on the bi- similar to C milleri in its biol- ology and ecology of C. milleriy ogy and 2-year life cycle except including natural enemies and that its generations, like C. pathogens, relationship of cli- starki, are established every even-numbered year. The effects matic and physiographic infiu- of its infestations are less severe ences to successive generations of than those of C milleri. needle miners, and field tests of To gather more data about C. insecticides. HOSTS AND DISTRIBUTION Lodgepole Pine at breast height. These were growing among scattered, heav- A subspecies of lodgepole pine ily infested, older trees and the (P.