Something eating my raspberry plants - the green ...

If you don't see anything munching on the leaves during the day, then it is probably slugs. Though raspberries aren't their favorite food, and the ones with thorns are deadly to them, they will eat the leaves

There are a lot of home remedies and store bought remedies.  Some people swear by beer set out in containers like tuna cans at soil level.  Sprinkling "sharp sand" or diatomaceous earth is a chemical free way of dealing with them.  Commercial pesticides are very effective and are sprinkled on the ground, not your plants, so are relatively safe (but the label probably cautions against applying around plants within two weeks of picking the fruit). 

It could be a lot of insects, but you should see anything that eats the leaves in the daytime.  That can include grasshoppers, caterpillars, beetles and aphids.  Another insect that feeds at night, besides slugs, is the Asiatic Garden Beetle.

You are going to have to examine your plants carefully in the daytime and at night until you can see for sure what is eating them.  Use a magnifying glass in the daytime in case the insects are really small and hard to see, like aphids.

Grasshoppers are about the easiest insect to spot, so you should know if you have them.

Could be baby grasshoppers, shake the branches and keep eyes on anything that moves!  Diatomaceous Earth can also be found at pool supply places. 

Hi,
  I agree with profitbob, but want to add this bit of info I've heard about, but have just never gotten around to trying. You can buy praying mantis eggs at some of the online garden supply stores and I do know these insects are a gardner's buddy for sure; they attack and eat almost any pest attacking your plants and while they are somewhat creepy looking, I actually kept one for a pet when our son was little and fed him insects I found here and there ( called him ET as that was about the time the movie came out ). You do need to check day and night to see if you can identify the pest and a good magnifying glass is essential, for some pests are very small and for those of us with impaired up close vision, its almost impossible to see the smaller aphids and mites that could be attacking your plants. If you must use pesticides, use them very sparingly on plants you plan to eat and follow the directions carefully. Also, you can contact your county extension agent and see what he or she recommends; they are always a good source of information.Hope this helps; Mark Savage, certified master gardner % Savage Gardens