Lab puppy biting other dogs

Question
Hi.  I have a 12 week old yellow lab male puppy.  He is wonderful but I am having one problem with him.  I have three other dogs: a male rottweiler, a female rat terrier and a female pug.  My lab bites (play bites) all of my other dogs, or at least tries to.  Both my Rottweiler and terrier will correct him (growl at him) and so he stops; however, my pug which is one year old and really small is scared of him at this point.  I think the reason is that she is not really able to "growl" and therefore he doesn't realize that he's hurting her when he bites too hard.  At first they played really well together but now they he's bigger than she is and he has hurt her with his playing biting she just runs from him.  Do you have any advice on how I can correct him for biting her?

Answer
Running away and refusing to play is a correction. Your job is to prevent the pup from following the other dog. You could also try getting the pug a spiked collar that will be uncomfortable to mouth. Of course I am assuming he's biting at the scruff because that's common.