Grothe also ran for 68 yards on nine attempts while Mike Ford, Moise Plancher and Jamar Taylor scored on the ground for the Bulls (5-0).
South Florida's defense made three interceptions and held the Wolfpack to 26 yards rushing.
N.C. State's Harrison Beck completed only nine passes on 32 attempts for 239 yards.
Andre Brown had 39 yards on nine carries and had two receptions for 85 yards. Owen Spencer had three receptions for 94 yards for N.C. State (2-3).