German cockroaches favor warm, humid spaces near food and water — kitchens, behind appliances, under sinks — and Harford's a four-season climate typical of the Pennsylvania mountains, with more snow than the Philadelphia area keeps them active most of the year. American cockroaches, larger and reddish-brown, prefer basements, drains, and utility rooms. Historic rowhomes and twin homes from the coal and industrial era, alongside newer construction in the Lehigh Valley's logistics corridor.
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.