Stink bugs have propogated their way across the USA in the last 5-7 years, and there's a variety of other bugs, fish, crustaceans, and even rodents that are prevalent that simply didn't exist here a decade or two or three ago.
Obviously some are accidental stow aways in cargo ships etc, but all of them? Why not force your enemy to deal with a common plague that your country already has?
I believe there is a Chinese beetle of some sort that is US-invasive and which damages lumber. I'm not sure how it arrives but these days I'm suspicous.
Emerald Ash Borer came from China and decimated Ash tree species, which is why you do not see that many around that do not look all sick.
Although there are lots of pests that have come from China that attack native species so you may be talking about a different type of beetle. Dont forget snakehead fish and Asian carp too.