Jeff zone 8 N.C.

Are you sure it is rot? Is the corm actually rotting? If it's just the leaves then it is probably shock from being repotted and moved to outside. If just leaves were lost then fertilize it with half strength liquid fertilizer and then definitely hold off on water. No leaves means it does not need water. If the underground parts are actually rotting then use hydrogen peroxide diluted with water to soak the corm.