16 October 2025
Remember the brown marmorated stink bug invasion? Halyomorpha halys was first noticed in Allentown PA in 1998 and soon spread across the state. By 2010 alien stink bugs were causing record damage in Pennsylvania orchards and annoying homeowners by invading tiny cracks in our homes at the first sign of cold weather. October used to be the worst month for this.
Studies back then predicted where the stink bug was likely to invade while USDA searched for a biological control. They were looking for a predator within the brown marmorated stink bug’s native range that would not pose a threat to North American species.
Meanwhile the stink bug continued to spread. By within 20 years it was thick in the I-95 Corridor, clearly established east of the Mississippi, and had spread in the Pacific coast states.
By 2018 researchers had settled on a safe non-stinging wasp, the Samurai wasp (Trissolcus japonicus), that lays its eggs inside brown marmorated stink bug eggs; its larva eats the egg from within. The map below shows the wasp’s potential range around the world. Its outlook as a solution in the eastern U.S. was great but it was marginal to unsuitable in the West.
Approvals to import the wasp were still grinding through the bureaucratic process when the Samurai wasp showed up on its own as described in this vintage article: Stinkbug Predator Shows Up On Its Own…