Lythrum salicaria
"Hylobius transversovittatus" seems to be host-specific to purple loosestrife "(Lythrum salicaria)". Before it was introduced into North America the weevil was tested on about fifty plants native to the continent to see whether they were susceptible to attack. Of these, only swamp loosestrife ("Decodon verticillatus") and winged loosestrife ("Lythrum alatum") were found to be potential hosts. It was found however that if purple loosestrife was available, it was preferred over these native species and the weevil was considered not to be a threat to non-target plants.