Just so you know that there are alternatives: I've baited vole traps with a sample of whatever they were feeding on in the garden. I'll be darned if I'm going to create something gourmet for them, lol!

I'll be that your slugs will not be quite so attracted to cuke and zucchini slices.

Hmm .. intriguing idea. They've been munching pea vine stems and kale leaves, both of which wilt quickly (and are available fresh nearby). But maybe sliced veggies or fruits ...

How about using Iron phosphate slug bait around the traps. You most likely want the slugs gone too.

Well, I got the big vole who gnawed a hole in the metal fence (!) and has been rampaging through the pea patch, etc. If I need to put out traps again I will put out some iron phosphate too  that is a good idea. I was hoping the garter snakes would get bigger and keep the slugs under control, but they haven't been able to keep up, and I'm getting tired of replanting seedlings that the slugs devour.

Sheesh, was gardening like this in Grandma's day? Too many critters to contend with!

We have a major problem with voles but were concerned about other animals and kids getting into the traps. So we've made a few 'enclosed' traps that seems to be working. Get PVC piping from your local hardware store in the size you would use for a sewage drain and have them cut it in 3-4 ft sections. Buy end caps the same size as your piping. Cut small holes in the end caps large enough for the voles to get into but small enough to keep other larger animals out. If you put the holes in the right place other animals (insects, snakes, etc) shouldn't crawl up to get inside of the trap. We mix mice poison with peanut butter and place inside the PVC pipe then put the end caps on each end. Lay these around on their sides (long ways) in your garden/yard in places that the voles travel around. You'll notice the peanut butter will disappear a little each day. If not, move the pipe to another spot. This has slowly dwindled the infestation we've had of voles but have a long way to go since we live in a wooded area off of a golf course (lots of food for the voles - they think its a perfect place to have made their home and MULTIPLY!).

Any hole in anything large enough for a vole to enter will be large enough for any slug, snake, chipmunk, or any other similar sized or smaller critter to enter. Any time you use poison baits you take a large chance that an unwanted critter will ingest these baits and if it does not kill them could make them very sick.
Placing any poison in your garden is not a good idea.