First arriving in New Zealand in the early1900s, Argentine stem weevil attacks cereals such as wheat, barley and maize, and pasture grasses such as perennial ryegrass.
Adults feed on the foliage but it is the larvae that cause the most damage.
Eggs 1mm in diametre are laid near the base of the stem. Larvae burrow into and mine the tiller, eventually killing it.
A single larva can destroy 3-8 stems, resultin in significant damage.