Help me identify these pests (JPG)
I've been recently plagued with little flies around the house and in my search for a solution I've come across a tip to find out whether those flies are actually fungus gnats. The tip was to place a chunk of raw potato onto the soil and the fungus gnat larvae should flock to it within a day, if they are indeed present. Well, it is now a couple of days later and there's no sign of fungus gnat larvae on any of the 10 potato chunks. There are however three other bugs that found the treats; one is clearly a little black snail, and the other two are different grubs or worms. I've included a photo of them all and I hope you can help me identify them, and maybe even offer a battle plan (or maybe they are all harmless)?