This article was downloaded by: [USDA National Agricultural Library] On: 6 January 2010 Access details: Access Details: [subscription number 917340536] Publisher Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37- 41 Mortimer Street, London W1T 3JH, UK Biocontrol Science and Technology Publication details, including instructions for authors and subscription information: http://www.informaworld.com/smpp/title~content=t713409232 Host range of the European, rhizome-stem feeding scale Rhizaspidiotus donacis (Hemiptera: Diaspididae), a candidate biological control agent for giant reed, Arundo donax (Poales: Poaceae) in North America J. A. Goolsby a; P. J. Moran a; J. J. Adamczyk a; A. A. Kirk b; W. A. Jones b; M. A. Marcos c; E. Cortés c a United States Department of Agriculture, Agricultural Research Service, Kika de la Garza Subtropical Agricultural Research Center, Weslaco, TX, USA b USDA-ARS, European Biological Control Laboratory, Montpelier, France c Biodiversity Research Institute (CIBIO) University of Alicante, Spain First published on: 26 August 2009 To cite this Article Goolsby, J. A., Moran, P. J., Adamczyk, J. J., Kirk, A. A., Jones, W. A., Marcos, M. A. and Cortés, E.(2009) 'Host range of the European, rhizome-stem feeding scale Rhizaspidiotus donacis (Hemiptera: Diaspididae), a candidate biological control agent for giant reed, Arundo donax (Poales: Poaceae) in North America', Biocontrol Science and Technology, 19: 9, 899 — 918, First published on: 26 August 2009 (iFirst) To link to this Article: DOI: 10.1080/09583150903189099 URL: http://dx.doi.org/10.1080/09583150903189099 PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. Biocontrol Science and Technology, Vol. 19, No. 9, October 2009, 899Á918 RESEARCH ARTICLE Host range of the European, rhizome-stem feeding scale Rhizaspidiotus donacis (Hemiptera: Diaspididae), a candidate biological control agent for giant reed, Arundo donax (Poales: Poaceae) in North America J.A. Goolsbya*, P.J. Morana, J.J. Adamczyka, A.A. Kirkb, W.A. Jonesb, M.A. Marcosc, and E. Corte´sc aUnited States Department of Agriculture, Agricultural Research Service, Kika de la Garza Subtropical Agricultural Research Center, Weslaco, TX, USA; bUSDA-ARS, European Biological Control Laboratory, Montpelier, France; cBiodiversity Research Institute (CIBIO) University of Alicante, Spain (Received 21 June 2009; returned 6 July 2009; accepted 14 July 2009) The armored scale Rhizaspidiotus donacis (Leornardi) was evaluated as a potential biological control agent of the invasive reed grass Arundo donax in North America. No-choice tests, native range field surveys and non-target host exposures were used to determine the fundamental host range of the scale collected from Caloma, Spain and Perpignan, France. Thirty-five species, including two genotypes of A. donax and seven ecotypes of Phragmites australis, along with closely related grasses, economic grasses and habitat associates were tested. In quarantine no-choice testing using releases of 200 crawlers per plant, normal development of R. donacis was observed on A. donax and A. formosana, with very limited survival to the adult stage on Spartina alterniflora and Leptochloa spp. In follow-up studies using 1000 crawlers per plant, 10 live adult females were found on Leptochloa virgata, and one adult female on Spartina alterniflora, but average adult female abundance per plant was (2580%) 26-times lower on L. virgata and over (39,090%) 100-times lower on S. alterniflora than on A. donax. Field surveys were conducted at five locations in Spain and France at which A. donax infested with R. donacis, co-occurred with two non-target species of concern and R. donacis was only found on A. donax. Six-month field host exposures in Spain using potted Leptochloa plants entwined with heavily infested A. donax confirmed that R. donacis is specific to Arundo under field conditions. Based on our results, the scale R. donacis appears to be specific to the genus Arundo and is unlikely to harm native or cultivated plants in the Americas. Downloaded By: [USDA National Agricultural Library] At: 15:14 6 January 2010 Keywords: biological control of weeds; host specificity testing; invasive grasses Introduction Arundo donax is native to the Old World from the Iberian Peninsula and Mediterranean coast of Europe to south Asia, including North Africa and the Arabian Peninsula. It has been cultivated in the Old World for thousands of years as a fiber crop and source of reeds for wood wind instruments. It was later widely introduced around the world for roof thatching, craft making, and erosion control. Subsequently, it has become naturalized and invasive in many tropical, subtropical, *Corresponding author. Email: [email protected] First Published Online 26 August 2009. ISSN 0958-3157 print/ISSN 1360-0478 online # 2009 Taylor & Francis DOI: 10.1080/09583150903189099 http://www.informaworld.com lo 900 J.A. Goolsby et al. and warm-temperate regions of the world. Arundo donax is an invasive weed of riparian habitats and irrigation canals of the Rio Grande River Basin and the southwestern US (Everitt et al. 2004; Spencer, Ksander, and Whitehand 2005; Quinn and Holt 2008). Giant reed, also known as carrizo cane, dominates these habitats, which leads to loss of biodiversity, alters channel morphology, damages bridges, increases costs for chemical and mechanical control along transportation corridors, and impedes law enforcement activities on the international border (Goolsby and Moran 2009; Moran and Goolsby 2009; Yang, Goolsby, and Everitt 2009). Additionally, this invasive weed consumes large amounts of water (Watts and Moore, unpublished data) and competes for water resources in an arid region where these resources are critical to the environment, agriculture and municipal users (Seawright et al. 2009). Biological control of A. donax with insects may be the best long-term option for managing this highly invasive weed. Tracy and Deloach (1999) reviewed the feasibility of biological control for A. donax and noted that several insects are known to feed on it in Africa and Europe. One of these insects, Rhizaspidiotus donacis (Leonardi), the Arundo scale, was selected for further evaluation because it appeared to be one the most widespread and damaging arthropods associated with A. donax in the subtropical regions of its native range in Mediterranean Europe (Figure 1). Rhizaspidiotus donacis occurs with the Arundo wasp, Tetramesa romana Walker, most notably in the western Mediterranean (Portugal, Spain, and south- western France). Populations of T. romana from Mediterranean Europe were permitted for release in Texas, USA in April 2009. Both the original description of Rhizaspidiotus donacis (as Targionia donacis, later transferred to Rhizaspidiotus by Ferris 1943) and other collections from the native range (reviewed by Balachowsky 1932, 1951) in France (Balachowsky 1930, 1933, 1951), Spain (Balachowsky 1935; Gomez-Menor Ortega 1958; Martin-Mateo 1983), Italy (Lupo 1957), and North Africa (coastal Algeria) (Balachowsky 1928) indicate that R. donacis has been collected only from Arundo donax, with the exception of one report from Turkey (Uygun, Sengonca, Erkilic, and Schade 1998) that indicated a collection from common reed (Phragmites australis) a finding inconsistent with our own field collections. Possibly, the plant was misidentified and was actually A. donax, which is known to occur in this part of Turkey. Downloaded By: [USDA National Agricultural Library] At: 15:14 6 January 2010 Figure 1. Rhizaspidiotus donacis scale on Arundo donax. Biocontrol Science and Technology 901 The genus Rhizaspidiotus MacGillivray contains 13 mostly Palaearctic members (Kosztarab and Kozar 1988; Ben-Dov and German 2003), including both mono- phagous/oligophagous and polyphagous species. Besides the Arundo scale, one other species, Rhizaspidiotus secretus (Borchsenius), uses Arundo donax and other Arundo spp. as hosts as well, including Phragmites australis. This species is found in Tajikistan, Pakistan and Afghanistan (Danzig 1993). A Russian species, Rhizaspi- diotus graminis Borchsenius, feeds on Arundiella spp. (Danzig 1993). Two European/ Mediterranean species in addition to the Arundo scale feed on grasses: Rhizaspi- diotus balachowskyi Kozar & Matile-Ferrero, found on Chrysopogon gryllus (Koza´r and Matile-Ferrero 1983), and Rhizaspidiotus bivalvatus Goux, found on Festuca arundinaceae and F. ovina (Balachowsky 1951). There is also a Chinese species, Rhizaspidiotus amoiensis Tang that feeds on Imperata spp. (Tang 1984). Literature records suggest that the grass-feeding Rhizaspidiotus species are host-specific at