Within the first mentioned group, ‘bushies’, Lies many nuisance species of cockroach, which, as the name suggests prefer the bushy surroundings of a building and will only enter once their preferred habitat becomes uncomfortable/uninhabitable usually due to prevailing weather conditions to seek refuge. They aren’t typically regarded as a pest species due to their preference for external areas.
Preventative treatments which are undertaken for this pest group will often focus on their favoured harbourage within external areas. These locations are often not favourable for modern pesticides with UV light and weathering often breaking the active down. The internals of a structure should also have a treatment undertaken to prevent possible internal harbourage sites and to ensure the pest is eradicated if it does enter the structure. In practice for these pest species’, environmental changes are the best prevention. Removing dense vegetation, leaf litter and plants which hold water along with encouraging ventilation and light surrounding the structure will reduce harbourage immensely and sealing the structure with insect screenings and weather strips at opening doors and windows as well as sealing around penetrating pipes etc will help prevent pest ingress.

Then comes the much feared ‘largie’. This group contains two of the more common pest species, Periplaneta americana (the American cockroach) and Periplaneta australasiae (the Australian cockroach). These cockroaches have very little aesthetically different, with the Australian cockroach having one yellow marking on each forewing just behind the pronotum (protective head covering) and the American cockroach lacking these markings. Their regurgitation marks and ootheca (egg casings) stuck on surfaces is often a good indication of harbourage and infestation. These cockroaches take advantage of modern building practices, choosing to reside in voids within kitchens, walls, roofs, subfloor areas, furnishing and drainage systems.
Treatment of this pest group requires a sound working knowledge of the pest groups biology and ecology, likely harbourage and useful products and application equipment that will increase the products effectiveness. The treatment is far safer and more effective when harbourage site treatment (crack, crevice and void focused) is implemented in favour of the more common, out dated, skirting board spray treatment style. An appropriately trained pest professional should have an in-depth knowledge of pesticide groups, formulations and modes of action and should be able to choose the appropriate product dependent on pest pressure and treatment areas. Hygiene is also top of the list in prevention, cleaning spills, sealing waste and sealing left over or stored food products especially of a night while the building is dormant. Places like sinks, drains and under fridges/dishwashers which often hold food and water should have special attention paid to them. Again sealing external access points around doors, windows and pipework will help prevent pest ingress.

Last but certainly not least is the synonymously invasive Blatella germanica (german cockroach). The adult German cockroach is small in size (10-15mm) pale brown in colour and has two distinct laterally running lines on its pronotum. The female will often be seen carrying the ootheca which is pale brown in colour and similar in shape and size to a tic-tac. This cockroach is well known for its invasive nature with its favoured harbourage sites in the wet areas (kitchens, bathrooms and laundry’s) of houses and commercial premises. Unlike other pest cockroach species the German cockroach very rarely flies or harbours externally travelling from building to building on items such as electrical appliances, boxes, groceries and even in hand bags which they will dislodge from and quickly seek refuge. These cockroaches have an extremely fast breeding rate and under favourable circumstances populations may reach 1000 within 1 year from a single couple.
Treatments for this pest species is a job for a highly skilled and trained pest professional. Its resilience to treatment often becomes very apparent in the 2-3 week period following an unsuccessful treatment with populations quickly rebounding to an unacceptable level. Due to fast breeding rates and failed treatments chemical resistance in this species becomes an issue with many strains showing resistance to one of the most commonly used chemical groups, synthetic pyrethroids. When shopping for a treatment for this pest species the importance of a service warranty cannot be understated. Hygiene is vital in the maintenance of this pest species, with the abundance of water, food and harbourage sites, comes an abundance of cockroaches. This particular species requires a high water intake. While a lot of moisture may be gained from their food any excess water should be removed in an effort to reduce its availability. In most cases non chemical control measures, although they will noticeably reduce populations will not grain appropriate control without the integration of a chemical control plan.