The official ruled out what would have been a winner from Davies towards the end of the game at the Reebok Stadium, and after the game Davies suggested the referee had "something personal" against him.
Warnock has been charged following comments made after Palace's FA Cup fifth-round tie with Aston Villa on February 14.
Warnock called for assistant referee Trevor Massey to be banned for incorrectly awarding the corner which led to Villa's late equaliser in the 2-2 draw at Selhurst Park.
Blackwell has also been charged in relation to an incident during United's Championship game with Nottingham Forest on February 16.
The United boss was critical of the referee after Darius Henderson was shown a straight red for what was deemed to be an elbow on Forest's Paul Anderson.
The FA confirmed the trio have until March 12 to respond to the charges.
Meanwhile, Derby's Jay McEveley has been fined £2,500 and warned as to his future conduct by the FA after admitting a charge of improper conduct following an incident in the Rams' ill-tempered encounter with Swansea last week.
McEveley received his marching orders for a second yellow card in Derby's 1-0 defeat and vented his frustration by kicking over drink bottles on his way to the tunnel.
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