Occurrence of the alien zigzag elm sawfly, Aproceros leucopoda (Hymenoptera: Argidae), in arboretums and botanical gardens of Hungary

Abstract

Background and purpose: The invasive alien zigzag elm sawfly, Aproceros leucopoda (Hymenoptera: Argidae), native to East Asia, was identified as a new pest of elms (Ulmus spp.) in Europe in 2003. Following the first records in Poland and Hungary, it has been found in many other European countries. Plant taxa on which damage by larval feeding has been observed under natural conditions either in Asia or in Europe all belong to the genus Ulmus. Ulmus pumila (including var. arborea) seems to be a preferred host, but other species have also been reported as having suffered severe defoliation by the pest. One objective of our study was to complete information on the distribution of the sawfly species in Hungary. Moreover, we searched for Ulmus taxa which might be affected under natural conditions.

Materials and methods: To provide data on distribution and susceptible elms, we carefully checked Ulmus taxa for the presence of any juvenile developmental stages of A. leucopoda and the characteristic feeding traces on leaves in 17 arboretums and botanical gardens throughout Hungary in 2011 and 2016.

Results and conclusions: We have recorded A. leucopoda or only the clear symptoms of damage by it at all the locations visited and totally on 20 Ulmus taxa. We have identified 14 of these for the first time as being susceptible to the pest. We suggest that the suitability for egg laying and sensitivity to at least partial damage by A. leucopoda of the damaged taxa should be considered before planting them for any purposes.