What insects eat swede plants

Root fly, cut worms... there is a host of beasties out there happy to eat your veggies

You could try various other methods to stop slugs eating your veggies without poisoning birds, hedgehogs, etc, which eat the slugs. Read my blog on slugs and snails. You could also try reading my blog on companion planting for ideas on plants to grow with veggies whilst deterring pests.