PROC. ENTOMOL. SOC. WASH. 112(2), 2010, pp. 246–257 LELUTHIA ASTIGMA (ASHMEAD) (HYMENOPTERA: BRACONIDAE: DORYCTINAE) AS A PARASITOID OF AGRILUS PLANIPENNIS FAIRMAIRE (COLEOPTERA: BUPRESTIDAE: AGRILINAE), WITH AN ASSESSMENT OF HOST ASSOCIATIONS FOR NEARCTIC SPECIES OF LELUTHIA CAMERON ROBERT R. KULA,KATHLEEN S. KNIGHT,JOANNE REBBECK, LEAH S. BAUER,DAVID L. CAPPAERT, AND KAMAL J. K. GANDHI (RRK) Systematic Entomology Laboratory, Plant Sciences Institute, Agricul- tural Research Service, U.S. Department of Agriculture, c/o National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, MRC 168, Washington, DC 20013-7012, U.S.A. (e-mail: [email protected]); (KSK, JR) U.S. Forest Service Northern Research Station, U.S. Department of Agriculture, 359 Main Road, Delaware, OH 43015, U.S.A.; (LSB) U.S. Forest Service Northern Research Station, U.S. Department of Agriculture, Michigan State University, 1407 S. Harrison Road, East Lansing, MI 48823, U.S.A.; (DLC) Department of Entomology, Michigan State University, East Lansing, MI 48824, U.S.A.; (LSB) U.S. Forest Service Northern Research Station, U.S. Department of Agriculture, Michigan State University, 1407 S. Harrison Road, East Lansing, MI 48823, U.S.A.; (KJKG) Daniel B. Warnell School of Forestry and Natural Resources, The University of Georgia, 180 E Green St., Athens, GA 30602, U.S.A. Abstract.—Published host associations are assessed for Leluthia astigma (Ashmead), Leluthia floridensis Marsh, and Leluthia mexicana Cameron, the three known species of Leluthia Cameron in the Nearctic Region. Leluthia astigma is reported as a parasitoid of Agrilus planipennis Fairmaire, emerald ash borer (EAB), infesting Fraxinus americana L., white ash, in Delaware County, Ohio. It is the first species of Leluthia for which a determined species of Agrilus Curtis has been confirmed as a host and the association vouchered. All other hosts reported in the literature for L. astigma require confirmation through rearing from an isolated host or documentation of an unequivocal host-parasitoid association. Leluthia astigma adults reared from parasitoid cocoons collected in Delaware County, Ohio parasitized and produced F1 adults in the laboratory on last-instar EAB larvae collected in Ingham County, Michigan. Parasitism of EAB and other natural history data are reported for L. astigma, including the first records of L. astigma from Kansas and New York. Key Words: ash, biological control, emerald ash borer, exotic, Fraxinus, invasive, natural enemies, Nearctic DOI: 10.4289/0013-8797-112.2.246 Doryctinae is a large subfamily of worldwide listed in Yu et al. (2005). Braconidae with 1,335 valid species Leluthia Cameron currently contains 17 species, with eight, five, three, and one * Accepted by Michael W. Gates in the Palearctic, Neotropical, Nearctic, VOLUME 112, NUMBER 2 247 and Australasian regions, respectively Eupelmus pini Taylor (Eupelmidae) (Belokobylskij et al. 2004, Yu et al. (Duan et al. 2009), and an undescribed 2005, Belokobylskij and Maetoˆ 2006). species of Atanycolus (Cappaert and Species of Buprestidae, Cerambycidae, McCullough in press). Duan et al. and Curculionidae (Coleoptera) have (2009) reared Dolichomitus vitticrus been reported as hosts (Wang 2001, Townes and one undetermined species Yu et al. 2005). The following three each of Cubocephalus Townes and species of Leluthia are currently known Orthizema Townes (Ichneumonidae) from the Nearctic Region: Leluthia from green ash (Fraxinus pennsylvanica astigma (Ashmead), Leluthia floridensis Marsh.) trees infested with EAB but Marsh, and Leluthia mexicana Camer- was not able to confirm parasitism of on. Hosts and/or host plants have been EAB. Additionally, Oobius agrili reported for all three species in the form Zhang & Huang (Encyrtidae), Spathius of published host/host plant lists or agrili Yang (Braconidae), and Tetrasti- statements that certain hosts/host plants chus planipennisi Yang (Eulophidae) are utilized. All reported hosts are have been imported from China and wood-boring beetles, including L. as- released in the U.S. for classical tigma from five species of Agrilus biological control of EAB since 2007 Curtis (Buprestidae). However, Noyes (Bauer et al. 2008). (1994) and Shaw (1994) demonstrated Leluthia astigma was reared recently that many host-parasitoid associations from parasitoid cocoons associated with in the literature are unreliable, and EAB cadavers dissected from infested Noyes (1994) recommended that spe- white ash (Fraxinus americana L.) trees cialists should verify the validity of in Delaware County, Ohio. Adult wasps associations reported in host-parasitoid reared from the cocoons parasitized and lists. produced F1 adults in the laboratory on Records of L. astigma from species last-instar EAB larvae from Ingham of Agrilus in North America are of County, Michigan that were inserted interest due to the establishment of the into green ash sticks. The new host exotic invasive pest Agrilus planipennis record, observations on parasitism in the Fairmaire, emerald ash borer (EAB), in laboratory, and other previously unre- North America. Emerald ash borer has ported natural history data for L. astig- killed tens of millions of ash (Fraxinus ma are reported herein. Additionally, an L.) trees in North America and is assessment of the published parasitoid- expected to kill millions more as it host-host plant associations for all spreads throughout the continent (Cap- Nearctic species of Leluthia is provided. paert et al. 2005). Biological control is considered the primary management MATERIALS AND METHODS tool for EAB in forested areas of North Through a collaborative effort among America, and the following species U.S. Department of Agriculture Forest have been reported as parasitoids of Service scientists and a Delaware City EAB in the U.S.: Atanycolus hicoriae Schools teacher at Dempsey Middle Shenefelt, Atanycolus simplex Cresson, School, 7th and 8th grade science stu- Spathius floridanus Ashmead (as Spa- dents studied EAB at Dempsey Wet- thius simillimus Ashmead) (Braconi- lands (40818.4860N83805.0870W), a 15 dae), Phasgonophora sulcata West- ha school forest in Delaware, Ohio. wood (Chalcididae), Balcha indica Dempsey Wetlands consists of mature (Mani & Kaul) (Eupelmidae) (Bauer et forest, old fields, and various succes- al. 2005, 2008; Duan et al. 2009), sional stages. The mature forest is 248 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON Figs. 1–3. Fig. 1. Dempsey Middle School student removing bark from ash. Figs. 2–3. Leluthia astigma. 2, Section of white ash isolated for rearing. 3, L. astigma cocoon and emerald ash borer cadaver. Arrows: a ¼ cocoon, b ¼ head capsule of cadaver. Scale bar ¼ 2 mm. dominated by species of Carya Nutt. undetermined ash species, were felled (hickory), Quercus L. (oak), and Ulmus in December 2008. The main trunk of L. (elm); the early successional areas each tree was cut into 1-m logs. One log are dominated by species of ash, Prunus from each tree was caged individually serotina Ehrh. (black cherry), and elm. to collect emerging insects; the bark Bothgreenashandwhiteashare was removed from those logs in August present and compose 10% of the mature and September 2009 after all insects forest trees and 23% of the early had emerged. The other logs were successional area trees (K. Knight and stored outside until January 2009 when J. Rebbeck pers. obs.). The project they were brought into the classroom began in 2006 after the discovery of progressively through February 2009 EAB in a private woodlot adjacent to for students to gather data on EAB Dempsey Wetlands in 2005. Parasitoid and collect insects inhabiting the logs. cocoons were observed in EAB galler- Bark was removed from each log using ies in ash trees at Dempsey Wetlands in a drawknife (Fig. 1), and insects found January 2008 (KJKG); efforts to rear in the phloem were collected. When a parasitoids from EAB larvae and para- parasitoid cocoon or parasitized EAB sitoid cocoons started in 2009 (KSK, larva was encountered, the drawknife JR, LSB). wasusedtoremoveasectionof A total of 29 ash trees, consisting of sapwood containing the cocoon or four green ash, 24 white ash, and one parasitized larva. All parasitized larvae VOLUME 112, NUMBER 2 249 were identified as EAB at the time of wasp pair (F0) was placed in a 355 ml collection (KSK); identifications were plastic drinking cup with a snap cap. confirmed for a portion of those larvae The cup contained three or four 0.8–1.2 through subsequent examination (DC). cm diameter 3 8.0 cm long, freshly cut All other insects were collected and green ash sticks, each infested artifi- preserved in 70% ethyl alcohol. Percent cially with a last-instar EAB larva. cover of EAB galleries was estimated Emerald ash borer larvae used in the by placing a grid in six locations on exposures were collected from infested each peeled log and counting the green ash trees in Ingham County, number of grid cells occupied by EAB Michigan using drawknives. They were galleries. Logs from which the bark was identified as EAB in the field and removed and insects were collected transported alive to the laboratory were subsequently caged together in where they were inserted into ash sticks growth chambers; insects that emerged by peeling up a bark flap on a stick with from the logs throughout spring and a knife, cutting an elongate channel in summer were collected and preserved in the wood with a linoleum cutter, placing 70% ethyl alcohol. a larva in the channel, replacing the Parasitoid cocoons and parasitized bark flap, and sealing it closed with EAB larvae (within a section of sap- Parafilmt. A 6.5 cm diameter hole was wood) were isolated individually in cut in the cap of each cup and closed 60.0 diameter 3 15.0 mm tall dispos- over with fine-meshed organdy to able polystyrene petri dishes. The petri provide ventilation. Thirty-seven expo- dishes were incubated at room temper- sures were carried out April 10–June ature in a cooler at the USDA Forest 22, 2009; they were maintained for Service Northern Research Station lab- either seven or 14 days in a growth oratory in Delaware, Ohio.