According to slughelp in UK, Spanish slugs aren't bothered by nematodes because the slugs don't really burrow underground.
I have found the only way to begin to control them is by hand, by the bucketful almost nightly.
I put them in soapy water. They die in moments.
Suggest starting early in the season.
Nemaslug doesn't work on this species, because nematodes live in the soil.
