Getting rid of Australian cockroaches, or Palmetto bugs, requires patience, persistence, and a combination of both chemical and non-chemical methods. Like most pests, Australian roaches require three basic things to survive: food, water, and harborage. If you can eliminate even one of these things, particularly through proper sanitation, the roach population will either die or be forced to move someplace else. Control should be targeted at their harborages since they stay in these areas for large amounts of time.
Australian Cockroaches prefer to live outdoors, but they will easily set up residence indoors if they can find their way inside. Physical exclusion (e.g. caulking up cracks) is about keeping Australian cockroaches out, or at least making it harder for them to get in. This is useful since the cockroach population is proportional to the number of harborages available. Limit roach harborages by caulking cracks and crevices, repairing torn screens, and sealing holes around pipes and other fixtures with copper mesh or other suitable materials. Chemical treatments into cracks and crevices are also valuable since prolonged contact with treated surfaces will yield a high mortality rate.
Proper hygiene and sanitation are essential, forcing the cockroaches to travel further to find food and water, which increases the chances of contacting treated surfaces outside harborage areas. Remove food and water sources for roaches by practicing good sanitation, vacuuming daily, keeping food in tightly sealed containers, and removing standing water wherever possible.