Cockroaches are disgusting! They leave faeces and regurgitation in their trail contaminating food and surfaces. They are known to carry and spread disease to humans including salmonella and gastroenteritis. Recent studies also indicate that cockroach droppings can cause allergies.
Cockroaches breed quickly, particularly German cockroaches, so it is important that you don’t wait for an infestation. If you see one cockroach, you can be certain there are more hiding in dark places, coming out in the open when it is dark in their search for food. Cockroaches are mainly nocturnal so their activity occurs in the dark when you cannot see the extent of the problem, what they are crawling all over and what they are contaminating.
Cockroaches are resilient; they can live in all conditions and feed off anything. Cockroaches are thigmotactic which means they like confined spaces. They are known for resting in tight cracks and crevices and are able to squeeze into the smallest of gaps. They often live in wall cavities, roof void, drains, subfloors, garbage areas etc.
Surface sprays will kill cockroaches that are directly in the line of spray but will not be effective on an infestation. For peace of mind you want a professional job done which will continue to kill cockroaches that come into contact with areas that have been treated.