Zig-zagging across Central Europe: recent range extension, dispersal speed and larval hosts of Aproceros leucopoda (Hymenoptera, Argidae) in Germany

Abstract

Aproceros leucopoda, the zig-zag sawfly, an invasive pest of elms (Ulmus spp.), was found in two separate areas of Germany through July 2014, i.e., a northern area including the states of Berlin, Brandenburg, Mecklenburg-West Pomerania, Saxony and Saxony-Anhalt, and a southern area in Bavaria. A speed of self-dispersal of 45-90 km/yr has been calculated from earlier and present records. Observations of A. leucopoda in Belgium and the Netherlands during 2013, which are 360-610 km distant from records in Germany of that year, are interpreted as resulting from human-mediated jump dispersal. Larvae, feeding traces and cocoons were frequently found on the native elm species U. minor and U. glabra, whereas none could be detected on U. laevis. Other occurrences were often on Resista® elms, causing severe defoliation in a recent planting. New host plant records for A. leucopoda are: U. minor 'Webbiana', U. minor var. suberosa , and the Resista® cultivars U. 'New Horizon', U. 'Regal' and U. 'Rebona'. The future dispersal of A. leucopoda throughout most of Germany is expected, because at least U. glabra and U. minor are widespread in this country.

Applicability of coloured traps for the monitoring of the invasive Zigzag Elm Sawfly, Aproceros leucopoda (Hymenoptera: Argidae)

“…A range extension of the sawfly towards western Europe has been documented by recent reports from Belgium (Boevé 2013, Ravoet 2014), the Netherlands (Mol & Vonk 2014, 2015, the Czech Republic (JuráŠková et al 2014) and northeastern Germany (Blank et al 2014). Severe damage up to defoliation of most of the canopy caused by the larvae of A. leucopoda may occur in various elm taxa (Blank et al , 2014.Aproceros leucopoda is supposed to spread both actively and passively. Since the adult sawflies are strong fliers (Wu 2006), their natural expansion may result in new infestations (Blank et al 2014).…”

“…However, the human-mediated dispersal of various developmental stages of the pest as stowaways in road, rail etc. traffic and along corridors, or as contaminants of plants for planting via trade might also contribute to its range expansion , Zandigiacomo et al 2011, Artokhin et al 2012, Shchurov et al 2012, Glavendekić et al 2013, Blank et al 2014, Mol & Vonk 2014, 2015.…”

“…It was also reported from Moldova as early as 2008 (TimuŞ et al 2008), but misidentified as Arge sp. (Blank et al 2014). Aproceros leucopoda occurs also in the European part of Russia (Artokhin et al 2012, Lengesova 2012, Shchurov et al 2012, Lengesova & Mishchenko 2013; e.g.…”

“…However, the human-mediated dispersal of various developmental stages of the pest as stowaways in road, rail etc. traffic and along corridors, or as contaminants of plants for planting via trade might also contribute to its range expansion , Zandigiacomo et al 2011, Artokhin et al 2012, Shchurov et al 2012, Glavendekić et al 2013, Blank et al 2014, Mol & Vonk 2014, 2015.Considering the severe damage the invasive alien A. leucopoda is able to cause to its host plants , Zandigiacomo et al 2011, Artokhin et al 2012, Shchurov et al 2012, Vétek et al 2012, Blank et al 2014) and the lack of effective methods of trapping adults of the pest, there is an evident need for tools that could be applied for early detection and population monitoring purposes.Trapping is a convenient access to obtain large, general samples of Hymenoptera from most habitats. Malaise traps or yellow pan traps are often used, which work continuously contrary to a person collecting with a handnet.…”

“…Severe damage up to defoliation of most of the canopy caused by the larvae of A. leucopoda may occur in various elm taxa (Blank et al , 2014.…”