German cockroaches favor warm, humid spaces near food and water — kitchens, behind appliances, under sinks — and Reese's a four-season climate typical of the Great Lakes region, with real winter cold and consistent summer humidity keeps them active most of the year. American cockroaches, larger and reddish-brown, prefer basements, drains, and utility rooms. Older brick and wood-frame homes built during the region's auto-manufacturing boom, most with basements to handle harsh winters.
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.