1983 © The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com. Apiculture & Social Insects Molecular Identifcation of Leafmining Flies From Australia Including New Liriomyza Outbreaks Xuefen Xu, 1,3, Marianne P. Coquilleau, 1, Peter M. Ridland, 1, Paul A. Umina, 1,2, Qiong Yang, 1, and Ary A. Hoffmann 1,3, 1 Bio21 Institute, School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia, 2 Cesar Australia, 293 Royal Parade, Parkville, VIC 3052, Australia, and 3 Corresponding author, e-mail: xuefenx@student.unimelb.edu.au (XX), ary@unimelb. edu.au (AAH) Subject Editor: Scott Geib Received 8 March 2021; Editorial decision 15 June 2021 Abstract Some leafmining fy species are pests of agricultural and ornamental plants but they also include many spe- cies with little economic importance. The taxonomy of leafmining fies is often challenging because of putative cryptic species. Following new outbreaks of Liriomyza (Diptera:Agromyzidae) in Australia, we here characterize 13 dipteran leafminer species collected from Australia based on cytochrome c oxidase subunit 1 (COI) DNA barcodes, and we compare these with overseas data. We confrm barcodes of nine species from the Agromyzidae (Liriomyza sativae, L. huidobrensis, L. trifolii, L. bryoniae, L. chinensis, L. brassicae, L. chenopodii, Phytomyza plantaginis and P. syngenesiae) and one species from the Drosophilidae (Scaptomyza fava); we describe new haplotypes for some of these species. Furthermore, we provide the frst DNA barcodes for two species (Cerodontha milleri and Phytoliriomyza praecellens) from the Agromyzidae and one species (Scaptomyza aus- tralis) from the Drosophilidae. These fndings provide a baseline for DNA-based identifcation of pest Liriomyza incursions spreading across the Australian east coast in relation to other species already present in Australia. Key words: leafmining diptera, DNA barcoding, COI gene, agromyzidae, Drosophilidae The Agromyzidae are a family of small, morphologically similar fies whose larvae feed internally on living plant tissue, often as stem and leaf-miners (Spencer 1990). Most members of the genus Liriomyza (Diptera: Agromyzidae) are host-specifc or restricted to a small group of related plants, however, some species are highly polyphagous and have a strong propensity to colonize new plant hosts (Parrella 1987, Spencer 1990, Reitz and Trumble 2002). Twenty-four Liriomyza species are recorded as pests or potential pests of crops worldwide (Reitz et al. 2013). Among these, three polyphagous agromyzids are of particular importance as global crop pests: Liriomyza sativae Blanchard, Liriomyza trifolii Burgess, and Liriomyza huidobrensis Blanchard (Murphy and LaSalle 1999). Although indigenous to the Americas, they have spread to most parts of the world relatively re- cently, likely due to an increase in international trade in vegetable and horticultural produce (Spencer 1989, Scheffer et al. 2006, Reitz et al. 2013). Once established within a new region, introduced popu- lations are prone to developing outbreaks and can be notoriously diffcult to control (Scheffer and Lewis 2005, 2006; Reitz et al. 2013; Gao et al. 2017; Pratt et al. 2017). Leafmining fies cause direct damage when females puncture the leaf surface to lay eggs and to create feeding holes. The mining ac- tivity of larvae as they feed within leaves and stems of plants then leads to further damage, reducing photosynthetic capacity of the mined leaf area and causing a decline in the vigor, growth, and yield of plants (Reitz et al. 2013). The leaf punctures of Liriomyza spp. also act as a pathway for plant pathogenic bacteria and fungi. For example, wounds caused by the feeding and oviposition activities of L. trifolii, provide ingress points for plant pathogenic bacteria (Matteoni and Broadbent 1988) and fungi (Deadman et al. 2002). Leafminers can also transmit potyviruses, at least in experimental situations (Zitter and Tsai 1977). Liriomyza spp. are classic sec- ondary pests. Indiscriminate use of broad-spectrum pesticides leads to Liriomyza species outbreaks with the evolution of pesticide re- sistance and the elimination of parasitoids (Parrella and Keil 1984, Hidrayani et al. 2005, Gao et al. 2012, Reitz et al. 2013). Exotic polyphagous leafmining fies of the genus Liriomyza pose a signifcant economic threat to Australian agricultural and horticul- tural industries. In 2015, L. sativae was detected in the Australian Journal of Economic Entomology, 114(5), 2021, 1983–1990 https://doi.org/10.1093/jee/toab143 Advance Access Publication Date: 19 July 2021 Research Downloaded from https://academic.oup.com/jee/article/114/5/1983/6324055 by guest on 05 June 2022