Sim, ela precisará de um novo visto.
Do Consulado Geral do Brasil em São Francisco :
_25. I got married and changed my name on my new passport, but my visa, which has not expired, is still on my old one. Do I need a new visa or can I just travel bringing along the two passports? The name on the visa has to match with the one on the valid passport. In this case, it is advisable that you apply for a new visa in order to avoid problems with the Brazilian immigration authorities.