As part of the campaign against the emerald ash borer (EAB), American scientists in conjunction with the Chinese Academy of Forestry began searching in 2003 for its natural enemies in the wild, leading to the discovery of several parasitoid wasp species, including Spathius agrili.

[1][2] This wasp is a gregarious ectoparasitoid, meaning it lays multiple eggs on the surface of its host, and the larva feed externally.

The life cycle of S. agrili was found to be synchronized with that of its preferred host stages – the emergence of adult wasps took place when third and fourth-instar larvae of EAB were available.

The female wasps oviposit through the tree bark, paralyze the host larva and lay a clutch of eggs on the integument.

In natural settings, S. agrili will be unlikely to encounter and parasitize non-target larvae as it does not search other tree species.