Salix babylonica Salix babylonica Salix babylonica (Babylon willow or weeping willow; ) is a species of willow native to dry areas of northern China, but cultivated for millennia elsewhere in Asia, being traded along the Silk Road to southwest Asia and Europe. "Salix babylonica" is a medium- to large-sized deciduous tree, growing up to tall. It grows rapidly, but has a short lifespan, between 40 and 75 years. The shoots are yellowish-brown, with small buds. The leaves are alternate and spirally arranged, narrow, light green, 4–16 cm long and 0.5–2 cm broad, with finely serrate margins and long acuminate tips; they turn
Spathius agrili only attracted to select species of "Fraxinus" and to "Salix babylonica". In natural settings, "S. agrili" will be unlikely to encounter and parasitize non-target larvae as it does not search other tree species. This, in addition to other tests of host specificity, led to approval of the wasp for controlled releases in specific study sites in the United States for further research. Spathius agrili Spathius agrili is a parasitic non-stinging wasp of family Braconidae which is native to North Asia. It is a parasitoid of the emerald ash borer ("Agrilus planipennis" Fairmaire), an invasive species which has destroyed tens of