THE PEST SPECIES
Scavengers of the world, cockroaches eat almost anything, almost anywhere.They are survivors. Some of the 36,000 species are pests and are carriers of disease affecting humans.
They all have flat bodies, enabling them to hide under bark, in crevices (or run under doors). Legs are almost even and the antennae are long. The noticeable difference between nymphs and adults, apart from the size, is the lack of wings in the young. Even adults run rather than fly in most circumstances.At the end of each growth stage, the outer shell or cuticle splits and the almost white new stage emerges. It darkens in a couple of hours to again blend with the others.
GERMAN COCKROACHES: Adults 20-25mm and honey coloured. Prefers warm kitchens or storerooms inside buildings.
BROWN-BANDED COCKROACH: Adults are 20 25mm, honey and brown. Prefer to live in buildings but are less dependant on warmth.
AMERICAN COCKROACH: Adults to 55mm and deep red/brown. Prefer moist areas like drains, both inside and outside. Readily flies in warm climates.
SMOKY BROWN COCKROACH: Same size as the American but darker. Lives in tree hollows, under bark and enters buildings at night.
OTHER AUSTRALIAN NATIVES: There are hundreds of species, mostly found in gardens, but these are not generally considered as pests.
BIOLOGY
Eggs are carried by the female in a capsule. Hatching nymphs grow through a series of 5-12 molts.The larger species become adults in 9-12 months.The German cockroach can mature in 2-3 months, and with up to 40 eggs in a capsule, the “family” could number 20,000 in a year.
Cockroaches avoid light and prefer warm, moist situations close to a food source.Their indiscriminate feeding in such areas as sewers,
drains and garbage areas brings them in contact with disease organisms associated with dysentery, typhoid, hepatitis and tuberculosis. Cockroaches are also known to produce allergic reactions in humans and, in some instances, severe asthma attacks.
MANAGEMENT
Successful management begins with a thorough inspection to identify the species and to determine the extent and source of the infestation.
A program is prepared combining the elimination of food sources, gaps and crevices where they live, traps and selective use of compounds.The compounds used for cockroach control are of low mammalian toxicity and do not persist in the environment.These include a group known as insect growth regulators, which prevent the development to adulthood.Thus, no eggs are laid.The various compounds used are usually so pest specific that they have little effect on nontarget species.
