Asia
Mile-a-minute weed (Persicaria perfoliata)
Eggs are tan-colored, cylindrical, and covered with small deposits of darker-colored frass. Larvae are up to 3 mm long and have a creamy-yellow body and brown head capsule. Adults are teardrop-shaped and 2 mm long with longitudinal ridges in their elytra. They are black when they first emerge from pupation, but after a few days of feeding are covered in rust-colored deposits derived from plant sap.
Adults emerge in early spring and feed on young mile-a-minute leaves, leaving a characteristic “shot-hole” feeding pattern. Eggs are laid singly (40–130 per female) on buds, stems, and leaves. Hatching larvae burrow into plant nodes to feed within mile-a-minute stems, developing through three instars. At maturity, larvae drop or crawl to the soil to pupate. Total development time from egg to adult is 3–4 weeks, and there are 3–4 generations per year. The last generation adults overwinter in the soil or plant litter.
Larval mining in stems weakens the plant and stunts growth. Adult feeding at stem tips reduces growth and seed production while defoliation causes leaves and stems to curl and wither. At high densities, the combination of larval and adult feeding kills impacted vines.
Hough-Goldstein, J. and E.C. Lake. 2022. Mile-A-Minute Weed 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-2022-11-MILE A MINUTE WEED-A. https://bugwoodcloud.org/resource/files/26410.pdf