Sitting 19th in the Premier League table, Wolves have conceded 40 goals in 16 games, including 16 from set pieces and the most penalties and headed goals in the top flight.
Gary O'Neil hired and fired set piece coach Jack Wilson within just three months this season and Pereira now takes the reins needing to solve a defensive crisis.
"We will work on set pieces every day," he said.
"I know a way to improve this is with work, correct it and then try again, then correct and try again.
"We need to find a way to not allow goals to go in like we did in the past.
"We need to be more aggressive, more pro-active and not wait in the zone.
"We need to be more aggressive in the duels, man-to-man.
"We need to open our body to see the movements, because if we close the pitch with bad body movement, we cannot see the pitch and it means we cannot anticipate the movement.