Most bugs won't eat a plant that fast.

But I have heard that grasshoppers can be a big problem at certain times of the year.

You might have slugs. They love young pot plants. Look for slugs on your plants or look for the shiny slime trail they leave. I got slugged pretty bad this spring. I've heard that a layer of crushed eggshells around the base of each plant will stop slugs and snails from getting to it.

That might be fine for a back yard garden, but I would hesitate to use that out in the bush where animals such as bears, skunks or raccoons are attracted to eggs.

I read that slugs are attracted to beer and if you dig a small hole, and put a plastic cup with some beer in it, the slugs will go in and drown.

I bought this stuff at Canadian Tire called "Slug Bait". Scotts Eco Sense, Slug and Snail Bait | Canadian Tire