Bean help?

Question:I have bush beans in my garden and up until today they were doing great. I got a ton of beans and the right consistancy. Just perfect. I went out today to pick some more and a bunch of them had little holes on the side like a bug or worm had gotten into them, but whatever it was ate up the whole bean but left the skin. I sprayed some pesticide out there just now, but can anyone tell me what kind of pest it might be or how else to prevent it?

Answers:
I had the same problem last year i sprayed and it didnt help but i went out at night with a flashlight and it was small snails eating the beans i had to buy snail killer that you sprinkle on ground. hope this helps