Moira Dunn, Smriti Mehra, Cindy Schreyer, Kelly Robbins and Heather Bowie are a shot back at 3-under par.
Dibos, a nine-year veteran of the LPGA Tour, started hot with a pair of 15-foot birdies at her second and third holes, the 11th and 12th at Highland Meadows Golf Club.
She added a four-foot birdie at the 16th, the result of a beautiful wedge approach. One hole later, Dibos dropped another 15-foot birdie putt to get to 4-under.
'Some players may be, how do you say, used to being in the lead, but I am not,' said Pike, who hit only six fairways on Thursday. 'The best in the world are used to it, Im sure, and its great for me to be in the lead.'
Pike first broke into red figures at the sixth when she played an 8-iron to eight feet. She made it back-to-back birdies with a 12-foot birdie at the par-4 7th.
On her back nine, Pike made a pair of birdie putts from inside of 10 feet at Nos. 13 and 17 for her share of the lead.
'I hit it consistently off the tee. Even though the rough isnt that thick, you still need to position yourself in the fairway to get the best shot onto the green,' said Pike, an Australian who has been on tour for three years. 'So I was fortunate to hit it good off the tee and got some shots close enough to give myself birdie opportunities.'
Dunn got to 4-under through 11 holes but she drove into the trees at her 12th hole and failed to save par.
'I played very solid on a tough day,' said Dunn. 'It turned out to be a good round and a good score.'
Jane Egan, Luciana Bemvenuti, Vickie Odegard, Jennifer Hubbard, Carin Koch, Dale Eggeling, Danielle Ammaccapane, Jane Crafter, Sara Sanders, Silvia Cavalleri and amateur Aree Wongluekiet all share eighth place at 2-under par.
Defending champion Annika Sorenstam struggled with two bogeys and one birdie in round one, en route to a 1-over 74.
Karrie Webb, who completed the career Grand Slam two weeks ago at the LPGA Championship, returned to competitive golf after the death of her grandfather and carded a 1-under 71, good for a share of 19th.
Full-field scores from the Jamie Farr Kroger Classic