German cockroaches favor warm, humid spaces near food and water — kitchens, behind appliances, under sinks — and Philipp's a climate defined by heat and humidity for most of the year, moderated only slightly by mild Delta winters keeps them active most of the year. American cockroaches, larger and reddish-brown, prefer basements, drains, and utility rooms. Older wood-frame construction is common throughout the Delta, much of it on crawl spaces that trap moisture given the region's high water table.
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.