Salix babylonica but beyond China, it has not generally been as successfully cultivated as some of its hybrid derivatives, being sensitive to late-spring frosts. In the more humid climates of much of Europe and eastern North America, it is susceptible to a canker disease, willow anthracnose ("Marssonina salicicola"), which makes infected trees very short-lived and unsightly. "Salix babylonica" (Babylon willow) has many cultivars, including: Various cultivars of "Salix matsudana" (Chinese willow) are now often included within "Salix babylonica", treated more broadly, including: Yet other weeping willow cultivars are derived from interspecific "Salix" hybrids, including "S. babylonica" in their parentage. The most widely
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