Signs of a Cockroach Infestation

Signs of a Cockroach Infestation

Cockroaches are night feeders that spend the day packed into cracks and voids, so the first signs of a problem are usually not the insects themselves. They are the traces left behind. Learning to read those traces tells you whether you have a wandering visitor or an established population, and roughly where it is living.

Droppings are the most reliable sign. Small cockroaches such as the German cockroach leave specks that look like ground black pepper or coffee grounds, often gathered in corners of drawers, along the back of a counter, in the hinge side of cabinet doors and under the sink. Large species such as the American and smoky brown leave cylindrical droppings with blunt ends and ridges along the sides, about the size of a grain of rice, that are easy to mistake for mouse droppings. Mouse droppings are pointed at the ends. Cockroach droppings are not.

Egg cases are the next thing to look for. A German cockroach egg case is a small brown capsule shaped like a purse, about a quarter inch long, and the female carries it until it is nearly ready to hatch, so you tend to find them empty, tucked into cracks near the harborage. American and smoky brown cockroaches glue theirs to surfaces in protected spots. Finding several egg cases means breeding is happening in the house rather than outside.

Shed skins are the pale, papery casts young cockroaches leave behind each time they grow. Several in one place mark a harborage. Smear marks, dark irregular streaks along wall edges and where surfaces meet, appear where cockroaches travel regularly in damp conditions. A heavy German cockroach population also produces a musty, oily odor that people describe as sweet or greasy once they learn to notice it.

Seeing a cockroach in daylight is the sign that matters most. Cockroaches hide during the day, and one out in the open at noon usually means the harborage is crowded enough to push some out. Several at once in daylight suggests a population well beyond what is visible.

Where to look follows from what cockroaches need: warmth, water and tight spaces. Check under and behind the refrigerator, inside the dishwasher door edge, behind the stove, under the sink around the plumbing, inside the top corners of cabinets and along the underside of drawers. Downstairs, check floor drains, the water heater area and the crawl space access. If you find droppings, egg cases or skins, leave them in place and note the spots. An inspection is free and carries no obligation, and the pattern of evidence helps a technician identify the species and place the treatment where the population actually lives.