Europe and Western Asia
Meadow knapweed complex (Centaurea ×moncktonii complex)
Adults emerge in spring to early summer, are up to 4 mm long, and have dark bodies. Wings are clear with two distinctly separate black bands followed by a “V” pattern. Females have long, black ovipositors. Eggs are laid in flower buds just starting to open. Larvae feed on receptacle tissue, forming woody galls. They are creamy white, barrel-shaped with retracting heads, and have dark anal plates. Larvae overwinter in galls inside the seed heads, and pupation occurs in spring.
Larval feeding directly destroys some seeds, possibly helping to reduce the rate of knapweed spread. In addition, galls drain nutrients from other parts of the plant, which causes stunting and reduces the number of flower heads produced.
Randall, C.B., J.E., Andreas, and J. Milan. 2023. Knapweed 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-2023-34-KNAPWEEDS-A. https://bugwoodcloud.org/resource/files/27451.pdf