Thanks for contacting Ask an Expert.
Slugs are a continual problem in our area especially with the rainy spring we have had. First, remember that what you see on your plants or on top of the soil is about 5% of the population. The rest on underground or under something. They are under boards, under steps, under vegetables during the day.
Organic measures to help you out are beer in a pie pan at ground level, check daily and remove dead slugs and add more beer. Sluggo is an organic method of getting rid of them and will not hurt your pets. It is iron phosphate. Sluggo should be slightly damp too.
Anything with metaldehyde in it is poisonous to pets and children.
However, you are doing the best thing by picking them off. I take a flashlight and go out after dark, with rubber gloves on and a plastic baggie. You can pick dozens (literally) off during that time. Remember that some of them are tiny little dots, gray and brown. So look for the small ones as well.
Slugs are always mating. Their eggs are often found under wood, wood chips, squash, etc. They are white and perfectly round in clusters of anywhere from 10 on up.
You might want to put boards down in the area you are seeing them eat and then check each morning and remove them. However, removing them by hand at night is your best bet. Or, get a couple of ducks, they will keep your population low. And, after going out for a week every night, my population was so low I did not put out Sluggo in the flowers for about a month.
Hee is an article with a bit more info. If you have more questions, don't hesitate to contact us. http://extension.oregonstate.edu/gardening/node/995