German cockroaches favor warm, humid spaces near food and water — kitchens, behind appliances, under sinks — and Wood River's a climate that behaves more like the upper South than northern Illinois, with shorter, milder winters keeps them active most of the year. American cockroaches, larger and reddish-brown, prefer basements, drains, and utility rooms. A mix of historic river-town homes, farmhouses, and government-corridor housing around Springfield, most with basements.
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.