Europe
Leafy spurge (Eurphorbia virgata), cypress spurge (E. cyparissias)
Spurgia esulaeand S. euphorbiae may in fact be one species, however a revision of this group has not been published. Both “species” are virtually indistinguishable. Eggs are orange and cylindrical. Larvae are orange and 1–2 mm long. Adults are dark gray with reddish abdomens and tiny, dark heads. Adults are just under 2 mm long; males are slightly smaller than females. Males have forceps on the end of the abdomen while females have an exposed ovipositor.
Adults emerge in spring when cypress and leafy spurge are resuming growth. They live only a number of hours. Eggs are laid in groups of 20+ among leaves on spurge growing tips. Hatching larvae feed on tips (through three instars), causing galls to form. Pupation occurs in silken cocoons within galls; adults emerge and repeat the cycle. There are two generations/year in cold climates and 3–5 in warmer areas if new shoots are available. Last-generation larvae overwinter and pupate in the soil.
Larvae attack spurge growing tips which destroys the shoot’s ability to flower and produce seeds. Shoots eventually die and are replaced by new stems that are attacked by the next generation of midges.
Milan, J., N.M. West, R.S. Bourchier, and C.B. Randall. 2024. Spurge 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-2024-40-SPURGES-A. https://bugwoodcloud.org/resource/files/29180.pdf