Yes, Abigail is largely to blame here, but again, other characters contributed to the witchcraft hysteria of Salem. Reverends Hale and Parris (at least in the first part of the play) feed the fires of the witchcraft rumors, as do the Putnams, who are bitter because of their seven dead babies. The judges and magistrates in this story are also co-conspirators through their subjective application of religious law. The only one who seems to be speaking with any degree of common sense is John Proctor, and for doing so, he is hanged. There is a great deal of deception and back-biting that transpires throughout the play itself, and it is this lying and hypocrisy that become greater sins than witchcraft by the play's end.

There are many other people to blame.

1.  The Putnams.  Mrs. Putnam was fixated on assigning blame for the death of her children.  She had already resorted to witchcraft to find out who "murdered" her children, so was quick to jump on the accusation band-wagon.  Thomas Putnam, we learn in act three, had been "prompting" his daughter to cry out against people whose land he wanted to take when they were imprisoned.

2.  Reverend Parris.  Quick to blame those who didn't like him, and to try to win favor in the town by being a lackey to the judges, Parris often sided against the townspeople, asking incriminating questions and giving the judges prejudiced backstories on people brough into the courts.  He also conveniently left out the fact that his own niece had been caught dancing and concocting spells in the forest; desparate to protect his reputation, he didn't tell this information.

3.  Danforth and Hathorne.  These judges often rejected logical fact, devised tricky scenarios and questioning, and refused to hear testimony that would prove the innocence of so many that were accused.  Once it became clear the accusations were false, they clung to their pride, refusing to recant convictions, so that their reputations wouldn't be foiled.

Those are just a few people that contributed, and were all too happy to jump in and ride the wave of accusations. I hope that helped; good luck!

Although Abigail Williams is very much to blame for the witch trials, she is certainly not the only one who is responsible.

After all, she is just a teenaged girl.  If she had brought these accusations forward and the adults in the community had not believed, nothing would have happened.  So, to me, the real blame lies with people like Parris and Hale and Danforth.  They are the ones who take the accusations seriously (for various reasons).

I would also blame the people like the Putnams who have power and use the trials to get more.  And I would blame the society as a whole for being so gullible that they would believe the girls.