Kirk Hanefeld, head pro at The International Golf Club in Bolton, Mass., will be in the first group today as he opens defense of his title when the 86th Charlie’s Maine Open Golf Championship gets under way at Riverside Municipal Golf Course in Portland.

Hanefeld will be teeing off at 7 a.m. with two competitors who played well in Tuesday’s pro-am, Jerry Diphilippo of Portland and amateur Mark Plummer of Manchester.

Diphilippo, a previous winner of the Maine Open, and Plummer, a 13-time winner of the Maine Amateur, each posted a 66 Tuesday, although Plummer, as an amateur member of his team, was playing from the white tees while Diphilippo, as his foursome’s pro, had to play from the back tees.

Plummer’s score can’t be discounted easily, though, because he has shot as low as 62 at Riverside from the back markers in winning the Casco Bay Classic in 1982.

Ron Bibeau, an assistant pro at Riverside, shot a 67, and David Gunas of Amston, Conn., was another stroke behind.

They can be considered among the other challengers to Hanefeld’s crown as well as Maine native Casey Bourque, a pro at Winnipesaukee (N.H.) Country Club who qualified for the U.S. Open earlier this year; former Maine Open champs Rich Parker of Lebanon, N.H., and Mike Colandro of Connecticut; 1997 Greater Bangor Open winner John Hickson of Bethel; Jim Becker of Poquonock, Conn., and Angel Franco of Asuncion, Paraguay.

Among the other top amateurs are Shawn Warren of Windham, who went to the U.S. Amateur; former Husson College of Bangor star Corey Poulin of Milford, and Toby Spector of Waterville.

Most of the pros from the Cleveland Golf Tour (formerly the New England Pro Tour) who have also been playing the in the New England state opens and other area events for years will have to miss the Maine Open because of a schedule conflict.

The tournament continues with 18 holes Thursday, after which there will be a cut for Friday’s 18-hole finale.