It started last year, but now parts of my garden are infested with grapevine snails. The adults are close to an inch across. I've catched about 700 of them this year, but there are hundreds of them left. Last year, all that was left of an giant clump of H. 'Fried Green Tomatoes' were some leaf stalks with a couple of threads, the remains of the veins.
Does spraying with an ammonia solution help, or does the shell protect them ?
PS: there's one good thing about it: I haven't seen a single slug this year.