Rep. Jim Gerlach’s (R) announcement this week that he will leave Congress to run for governor in 2010 touches off a competitive race in his suburban Philadelphia 6th district.

State Rep. Curt Schroder made his candidacy official Tuesday by announcing he would seek Gerlach’s seat, but he is not the only Republican interested.

Guy Ciarrocchi, Gerlach’s former chief of staff, and Chester County Recorder of Deeds Ryan Costello have also expressed interest in running. Several local Republicans have also mentioned that Chester County Commissioner Carol Aichele would be a good candidate for the seat, although she has already formed an exploratory committee to run for lieutenant governor.

Meanwhile, both local and national Democrats appear to have coalesced behind former editorial writer Doug Pike (D), who was endorsed by Rep. Patrick Murphy (D-Pa.) on Wednesday. Pike, the son of former Rep. Otis Pike (D-N.Y.), will likely put $1 million of his own funds into the race — a major advantage in the expensive Philadelphia media market.

Democrats have targeted Gerlach’s seat for several cycles without success, and last year they failed to recruit a good candidate to run against him. Nonetheless, Gerlach won re-election in 2008 with a slim 52 percent of the vote against a little-known candidate.