Assemblyman Vito Lopez’s sexual-harassment scandal exploded as a campaign issue in the hotly contested Queens state Senate race yesterday — when Republican Eric Ulrich slammed Democratic incumbent Joseph Addabbo for refusing to call for Lopez’s resignation.

Ulrich noted that Gov. Cuomo and other Democrats have urged Lopez to step aside.

“If Joe Addabbo can’t muster the courage to call on Vito Lopez to resign, then he shouldn’t be in office himself,” Ulrich said.

Addabbo said he won’t comment on “an ongoing investigation” but added, “Do I condone the activities alleged? Of course not.”

Lawmakers deemed two groping claims against Lopez credible; two other claims led to a $103,080 settlement.