Cockroaches need three things to establish a colony: food, water, and warmth. Dubuque's housing stock gives them exactly that. A blend of established manufacturing-era neighborhoods and newer suburban growth along the Mississippi River corridor. Combined with Dubuque's climate — a humid continental climate with hot, humid summers and cold winters, somewhat more humid than western Iowa given the Mississippi River's influence — indoor cockroach pressure rarely lets up on its own.
Treatment starts with locating the harborage points — the tight, warm, food-adjacent spaces roaches actually live in — and applying gel bait directly there rather than spraying open floor space. This targets the colony at its source and avoids the resistance issues that plague over-the-counter sprays. We follow up to verify the population has collapsed, not just scattered.