German cockroaches are the small fast ones that live inside, breeding behind the fridge, in the dishwasher door, inside the microwave hinge and along the kickboards. They arrive with cardboard boxes, second-hand appliances and the moving truck, which is why plenty of new Mernda homes have them within a year. The big Australian and American cockroaches come in from drains, garden beds and the subfloor in the older homes near the river when it is hot or wet.
Inside we use gel bait placed where the roaches actually hide, which they eat and carry back to the harbourage, and we treat the voids and hinges where the egg cases sit so the job is not repeating itself in six weeks. No spraying the benchtops and no emptying the cupboards. For the outdoor species we treat drains, subfloor vents and the base of the house.