© 2008 The Authors. Journal compilation © 2008 OEPP/EPPO, Bulletin OEPP/EPPO Bulletin 38, 507–509 507 Blackwell Publishing Ltd First record of Phytomyza gymnostoma Loew (Diptera: Agromyzidae) a leaf mining pest of leeks in Greece K. B. Simoglou 1 , E. Roditakis 2 , M. Martinez 3 and N. E. Roditakis 2 1 Prefecture Agriculture Directorate of Heraklion, Department of Plant Protection, Certification & Quality Control, Evans 60, 71201 Heraklion, Greece 2 Plant Protection Institute of Heraklion, National Agricultural Research Foundation, 71003 Heraklion, Greece; e-mail: e-roditakis@her.forthnet.gr 3 Institut National de la Recherche Agronomique, UMR CBGP, 2 place Pierre Viala (Bâtiment 16), 34060 Montpellier, Cedex 01, France In autumn 2007, an allium leafminer, Phytomyza gymnostoma Loew (Diptera: Agromyzidae), was recorded for the first time in non-commercial leek crops in the areas of Elassona and Katerini in Central Greece. Leek plants were severely damaged by the leafminer larvae infestation. Typical feeding symptoms were observed, caused by the mining behaviour of larvae within inner and outer leaves of leek plants, resulting in the formation of descending galleries. Pest control was performed locally using commercial insecticides with unknown efficacy mainly due to ignorance of the species biology. Introduction Onion (Allium cepa L.), leek (Allium porrum L.) and garlic (Allium sativum L.) are the most important allium crops in Greece. In 2006, a total of 13 000 ha were cultivated mainly in Northern and Central Greece (mostly in areas of Thessaloniki, Larissa, Pella and Trikala) (onions: 9200, leeks: 2100, garlic: 1700 ha). Approximately 213 thousand tonnes of onion (green and dry), 44 thousand tonnes of leeks and 13 thousand tonnes of garlic were produced. In order to cover the local consumption Greece also imports allium crop products. Imports in 2005 were estimated around 8 million USD. Greek exports are limited (garlic and onions, 680 000 USD), mainly to European countries and US (FAO, http://faostat.fao.org/). Allium crops have many pests, the most important being the onion thrips (Thrips tabaci Lindeman, Thysanoptera: Thripidae), the onion maggot (Delia antiqua (Meigen), Diptera: Anthomyiidae) the leek or onion moth (Acrolepiopsis assectella (Zeller), Lepidoptera: Acrolepiidae) and the leafminers (Diptera: Agromyzidae) (Alford, 2000). There are 7 leafminer species that have been reported as pests of allium crops. However there are only three species reported as pests of leek; Liriomyza chinensis (Kato), Liriomyza nietzkei Spencer and Phytomyza gymnostoma Loew. All three species have been reported in Europe (Dempewolf, 2004). The Allium leafminer P. gymnostoma (formerly Napomyza gymnostoma) is a pest of leek (A. porrum) and chives (A. schoenoprasum L.) and to a lesser extent of onion (A. cepa), garlic (A. sativum), shallot (A. ascalonicum L.) and of ornamental Allium plants (Agallou et al., 2004). The pest is causing extensive damage to crops in an increasing number of European countries. It has been reported as an Allium pest from Central, Eastern and more recently Western Europe, as well as in Asia from Turkey and Turkmenistan (Seljak, 1998; Zandigiacomo et al., 2002; Bouchery & Martinez, 2004; Collins & Lole, 2005; EPPO Reporting Service, 2005; MacLeod, 2007; Smith et al., 2007). The Allium leafminer larvae mine the leaves and bulbs, making the plants soft and susceptible to bacterial and fungal infections, such as white rot (Sclerotium cepivorum Berk). Heavy infestations completely destroy plants (Agallou et al., 2004; Collins & Lole, 2005). Adult flies are about 3 mm long, with a largely yellow head, black and yellow areas underside and dark legs with yellow joints between the femur and tibia. It has two generations per year in Central Europe. Adults emerge in the spring from pupae that overwintered within host plants. Females lay eggs at the base of host plant stems. The larvae of the first (spring) generation develop in garlic and onion stems and bulbs. First generation pupae diapause during the summer before adults emerge and lay eggs in leeks or other Allium species in the autumn, for the second generation. Pupae of the second generation overwinter in host plants, before adults emerge the following spring to lay eggs on hosts such as onions and garlic (MacLeod, 2007; EPPO Reporting Service, 2005). P. gymnostoma was added to the EPPO Alert List by the EPPO Secretariat in April 2005 following reports in the scientific literature that the organism was spreading within the EPPO region and becoming a significant pest of Allium crops (EPPO Reporting Service, 2005). However, at the 38th meeting of the EPPO Panel on Phytosanitary Measures, P. gymnostoma was removed from the Alert List 1 (EPPO Secretariat, 2006). 1 Editor’s note: the reason P. gymnostoma was removed was that it was widespread in the EPPO region.