I've used scent deterrents to discourage those munching pests, the one that worked best is a spray from HD or Lowe's called Critter Ridder. It smells and tastes bad, so you can spray it on the plants and around the area. Don't spray it when it's windy or it will make you sneeze and irritate your eyes - it has black pepper in it.
There are also granular scent deterrents that worked very well for us at the school garden when we had a bunny visiting. Just sprinkled it around the area on the ground. It lasts through watering and rain, as well.
