From what I can gather through research, the nematode solution is available in Europe, but not yet in the US. Ohio State University published an article in 2003 about research being done to see if US native nematodes would be effective, but apparently, our home-grown strain is not as deadly as the European strain.
The concern here has been damage to Earthworms. Perhaps more has been learned in the past few years, but on a quick search to answer your question, this is all I found.
As a life-long gardener I find the beer idea works best. Our courtyard is shady,
filled with hostas, shade loving flowers and a fish pond, all the ingredients for an
ideal habitat for slugs, along with the North Carolina humidity. I simply place 5 or
6 small custard dishes filled 1/2 with beer and the next morning collect hugh
quantities of the nasty critters. I have tried other products on the market but
find they didn't work as well and I dislike the idea of using chemicals.