The U.S. improved to 37 wins, one loss and four draws in the Gold Cup group stage.
Dike opened the scoring for the U.S. with a glancing header from a nice cross into the box from Matthew Hoppe.
The U.S. started hot after the break with Miles Robinson scoring before Dike netted a classy second to put Gregg Berhalther's side up 4-0 before the hour mark.
Emmanuel Riviere struck from the penalty spot to get Martinique on the scoreboard, but Gyasi Zardes offset that strike soon after with a clinical shot on the back of a nice team move to restore the four-goal lead for the U.S.
Nicholas Gioacchini added further gloss to the scoreline, finishing a close-range shot from a Busio cross to make it 6-1 in favor of the U.S.
Hoppe, who started, and Donovan Pines, who entered in the 70th, raised the total to 47 debuts in 31 matches under Berhalter.
Berhalter changed seven starters from last weekend's opening 1-0 win over Haiti, inserting defender James Sands along with Busio, George Bello, Eryck Williamson, Christian Roldan, Hoppe and Dike. The lineup averaged five international appearances and was in effect a junior varsity, with only Roldan regularly getting much time with the primary player pool.
Dike, coming off a breakout loan from Orlando to second-tier Barnsley in England's second-tier League Championship, raised his international goals total to three. He put the U.S. ahead in the 14th minute with a header off a long cross from Hoppe.
Next up for the U.S. is a Group B-deciding match against Canada on Sunday to see which nation takes top honors and earns a No. 1 seed in the quarterfinals.