[2] The adult Hylobius transversovittatus is a dark brown colour with two irregular transverse lines of tufts of white hair.

The females lay about 200 eggs over a period of two to three months with each being deposited singly near the roots of purple loosestrife or occasionally on the stem.

[4] The larvae undergo two moults over a period of one to two years before forming pupation chambers in the upper part of the root.

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.

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.

It is now found in large stands throughout the northeastern United States, southeastern Canada and the American Midwest where it crowds out other species and is a threat to biodiversity.