Europe
Oxeye daisy (Leucanthemum vulgare)
Eggs are scale-like and flattened and are less than 1 mm in diameter. They are transparent at first, but the head becomes visible just prior to hatching. Larvae are yellowish-white with brown head capsules and can be up to 9½ mm long at maturity. Pupae are light brown and may be found attached to or close to rhizomes. Adults are approximately 8 mm long with wingspans up to 16 mm. Adults rest with their speckled brownish-gray wings folded along their sides. Distinctive features of this species include the alternating light and dark bands running in parallel and perpendicular to the upper margin of forewings (observed as the bottom edge of wings when the moth is at rest).
Adults emerge in spring (typically April through June, depending on climate) and begin mating and ovipositing. Eggs are attached firmly to oxeye daisy leaves. Hatching larvae first feed within oxeye daisy leaves and stems before moving to stem bases and then to rhizomes, where they feed mainly internally. Flowering stems are not necessary for this species; larvae will develop fully on rosette parts. Larvae develop through five instars and are highly mobile when feeding; later instars are able to enter or exit host plant rhizomes and stems via holes they chew through the rhizome or stem walls. Larval frass (excrement) is sometimes seen covering the holes on the outside of infested rhizomes. Mature larvae typically overwinter within their feeding tunnels inside rhizomes or at the base of plant stems. Pupation occurs in early spring, and shortly thereafter new adults emerge. There is one generation per year.
Larval feeding reduces oxeye daisy above- and below-ground biomass and the number of flower heads produced.
De Clerck-Floate, R.A., S. Stutz, and J. Littlefield. 2024. Oxeye Daisy Biocontrol Agents: History and Ecology in North America. In: R.L. Winston, Ed. Biological Control of Weeds in North America. North American Invasive Species Management Association, Milwaukee, WI. NAISMA-BCW-2024-43-OXEYE DAISY-A. https://bugwoodcloud.org/resource/files/33582.pdf