Does a white marking on the back of the neck of a Bernese disqualify him from the show ring?

My Bernese Mountain Dog (11 wk male) is a gorgeous pup, and I'm not just saying that : ) His vet and several people in the know have told me he's the best looking Berner they've seen. However, he has a small tuft of white hairs (around 15 hairs) on the back of his neck and I want to know if that disqualifies him from conformation competitions. I checked the AKC website breed standards, but all they mentioned was a full white collar. Any idea? Thanks!