A 1-0 defeat at Sampdoria was a fifth reverse in six for Donadoni's men, who have slumped to 12th ahead of Sunday's meeting with Torino after becoming increasingly error-prone in both defence and attack.
The latest mistake came as goalkeeper Antonio Mirante mistimed his run on a free-kick to allow Samp's Mauro Icardi to tap home an easy finish at the Marassi, and Donadoni has had enough.
He told fcparma.com: "We need more passion and more conviction. We just can't go on missing every single chance and say 'sooner or later they'll start to go in'.
"We are conceding goals because of our own mistakes, not just because of our opponents' strengths."
Parma were riding high in the European places going into the new year but a haul of just six points from 2013 has invited criticism of the team's commitment to the cause.
"I think that is true of every team, not just Parma, and it would be too easy to blame our results on that," Donadoni added.
"I can see how hard the team is working, just as hard as they were in the first half of the season.
"But we can no longer afford to give anything else away and we have to pay more attention and concentrate. A good team like Torino is next up, and they've risen high up the league table."
McDonald Mariga, Fabiano Santacroce and Andrea Coda present injury concerns for Donadoni, while Torino miss Abou Diop, Alessio Cerci and Riccardo Meggiorini through suspension.
Torino president Urbano Cairo hopes his team put their chances away at the Tardini after watching various gilt-edged chances go begging in a goalless draw with Palermo.
Meggiorini, Giuseppe Vives, Rolando Bianchi and Paulo Barreto were all guilty of glaring misses but Cairo feels the Granata can make amends tomorrow.
"We need to keep working with the same intensity that we have shown in the last few weeks," Cairo told La Repubblica.
"As long as we start overcoming certain obstacles, I hope we can continue down the path we were on."