German Cockroach
Blattella germanica
CockroachesSmall, light brown cockroach with two dark parallel stripes behind the head. The most common indoor cockroach species and most difficult to control. Adults are 1/2 to 5/8 inch long. Most economically important and most persistent pest of houses, apartments, restaurants, and hotels in the United States. Adult cockroaches can squeeze through cracks as small as 1/16 inch (1.6mm). Has wings but does not usually fly. Exhibits gradual metamorphosis and nocturnal behavior. Prefers to live in protected cracks and crevices. Droppings look like dark smudges with dark dots. Reproduces rapidly with females producing egg cases (oothecae) that are yellowish and ribbed, about the size of a small fingernail, containing 30-48 eggs.
Control Methods
Recommended methods for controlling this pest
| Method | Type | Effectiveness | Requirements |
|---|---|---|---|
| Gel Bait Application for Cockroaches | Chemical | Required | |
| HEPA Vacuum Removal | Non-Chemical | None | |
| Door Sweep Installation | Mechanical | None | |
| Pipe Penetration Sealing | Mechanical | None | |
| Cabinet Gap Sealing | Mechanical | None | |
| Sticky Trap Monitoring | Non-Chemical | None | |
| Boric Acid Dust Application | Chemical | Required | |
| Clutter Reduction | Cultural | None | |
| Food Storage in Sealed Containers | Cultural | None | |
| Non-Repellent Residual Spray | Chemical | Required | |
| Crack and Crevice Aerosol | Chemical | Required | |
| Insect Dust Application to Voids | Chemical | Required | |
| Microencapsulated Formulation Application | Chemical | Required | |
| Threshold and Sweep Inspection and Repair | Mechanical | None | |
| Weep Hole Vent Installation | Mechanical | None | |
| Expansion Joint Sealing | Mechanical | None | |
| Glue Board Monitoring Stations | Non-Chemical | None | |
| Drain Gel and Foam Treatment | Chemical | None |
Common Harborage Locations
Where to find this pest during inspections
| Location | Why Found There | Priority |
|---|---|---|
| Under Kitchen Sinks | Moisture from leaks and condensation, warmth from drain water, darkness, food debris washed down, and minimal disturbance. | Critical |
| Kitchen Cabinets | Proximity to food sources, crumbs and spills, warmth from nearby appliances, dark undisturbed corners. | Critical |
| Pantries | Concentrated food sources, packages provide harborage, often undisturbed for long periods, dry environment. | Critical |
| Under Bathroom Sinks | High humidity from sink use, plumbing leaks, standing water in cabinet bases, warmth from hot water pipes. | High |
| Behind Toilets | Difficult to clean area, moisture from condensation and leaks, warmth from water supply, protected location. | High |
| Wall Voids | Protected from disturbance, temperature controlled, provides nesting material and travel routes throughout structure. | High |
| Behind Refrigerators | Consistent warmth from compressor motor, moisture from condensation, food debris falls behind, difficult to clean. | Critical |
| Behind Stoves | Heat from cooking, grease splatter, food debris, limited cleaning access, constant warmth. | Critical |
| Under Dishwashers | Warmth from motor, moisture from leaks and steam, food particles, dark protected space. | High |
| Behind Washers & Dryers | Warmth from dryer, moisture from washer, lint accumulation, minimal disturbance, dark space. | Medium |
| Wooden Furniture Joints | Cracks and crevices for harborage, darkness, near human activity areas. | Medium |
| Electrical Outlets | Warmth from electrical current, entry point to wall voids, protected hiding spot. | Medium |
| Electrical Panels | Significant warmth from electrical load, protected enclosure, rarely disturbed. | High |
| Indoor Garbage Cans | Direct food source, moisture, organic waste, daily accumulation of debris. | High |
| Floor-Wall Junctions | Natural collection point for debris, provides shelter, and travel routes. | Medium |
| Drop Ceilings | Undisturbed environment, warmth from lighting, provides routes between rooms. | Medium |
| Pet Food Bowls | Direct food source, water source, spilled kibble attracts pests. | Medium |
| Door Thresholds | Common entry point, gaps under doors, light attraction, temperature differential. | High |
| Storage Boxes & Clutter | Undisturbed environment, material for nesting, harborage between items, food source (cardboard/paper). | Medium |
Important Disclaimer: The information provided in this knowledge base is for educational and reference purposes only. Pest management professionals should always consult current product labels, Safety Data Sheets (SDS), manufacturer instructions, and applicable local, state, and federal regulations as the definitive source of truth. Product formulations, application methods, safety requirements, and regulations may change over time. This information may be out of date and should not replace professional judgment, proper training, or required licensing and certifications.