First report of Euaresta aequalis in Slovenia
The NPPO of Slovenia recently informed the EPPO Secretariat of the first record of Euaresta aequalis (Diptera: Tephritidae - burr-seed fly) on its territory, as E. aequalis is regulated by Directive 2000/29/EC as a ‘Non- European Tephritidae’. Species belonging to the Euaresta genus are endemic to the Americas and their larvae are associated with either Xanthium or Ambrosia. As some Xanthium and Ambrosia are important agricultural weeds, several Euaresta species have been introduced and released in different parts of the world for biological control.
In July 2008, E. aequalis was collected for the first time in Europe near Nova Gorica on Xanthium strumarium subsp. italicum. E. aequalis is native to North America and its larvae live in burrs of X. strumarium, destroying seeds. During summer 2012, additional findings were made at several places in the Vipava valley, as well as in bordering areas in Northeastern Italy. These results showed that E. aequalis is already widely distributed and has become established as an alien species in this part of Europe. It is noted that this is also the first time that X. strumarium subsp. italicum is recorded as a host plant of this fruit fly. It is possible that in this case the introduction of a new alien species will be beneficial, as E. aequalis might help reducing Xanthium weed populations. No phytosanitary measures were taken in Slovenia.
The pest status of Euaresta aequalis in Slovenia is officially declared as: Present, only in some areas.
Sources
NPPO of Slovenia (2014-06).
Seljak G (2013) The burr-seed fly, Euaresta aequalis (Loew) (Diptera: Tephritidae), new recorded in Europe, with new observations on its biology. Studia dipterologica 20(1), 31-38.