Pittsburgh has won six of its last eight contests to climb two games above .500.
The Pirates let a 2-0 lead get away in the fifth when J.P. Arencibia and Yunel Escobar hit home runs, but Pittsburgh came back in the sixth to take control of the game.
Lyle Overbay and Ronny Cedeno had back-to-back doubles off Brett Cecil (1-3) to open the sixth and Wood followed with his third home run of the season to give the Pirates a 5-2 advantage. Wood has had no more than five homers in any of his previous four major league seasons.
Jeff Karstens (6-4) was credited with the win, allowing two runs on five hits in seven innings.
Cecil, who made his first start since April 20, surrendered all six runs on eight hits in 6 1/3 innings.