Cockroaches

pests-australiancockroachAustralian Cockroach (Periplaneta australasiae)

Structure, Appearance and Characteristics

Adults:

  • Approx. 30-35mm in length.
  • Yellow border on pronotum (area behind the head) is very distinct.
  • Dark Reddish brown in colour.
  • Light markings on thorax.
  • Yellow streaks on the sides at the base of the wing covers (elytra).
  • Wings completely cover abdomen.
  • Chewing mouthparts.
  • Nocturnal.
  • Will fly in warm weather.

 

Nymph (The Young):

  • Look similar to adult but wingless.
  • Brown in colour until later instars (moults) which become more like the adult colouring.
  • Later instars posse’s distinct bright yellow spots along the margins of their abdomen.

 

Life Cycle

Gradual / Incomplete metamorphosis (egg – nymph – adult). Eggs are encased in an egg capsule (Ootheca). Female drops the egg capsule (Ootheca) shortly after it is formed near a food source, in crevices, on walls, or under workable material such as moist wood, so as to camouflage it. Eggs per capsule: 16-24. Incubation period: 30-40 days. Nymphal period: 6-12 months Nymphs normally moult 10-12 times to reach adulthood. Females may produce 12-30 egg capsules in a lifetime. Egg capsules are completed and dropped at about 10 day intervals. Adult lifespan: up to 8 months.

pests-americancockroachAmerican Cockroach (Periplaneta americana)

Structure, Appearance and Characteristics

Adults:

  • One of the largest of our pest species.
  • 35-40mm in length.
  • Reddish brown in colour.
  • Light markings on thorax.
  • Pale yellow border on pronotum.
  • Wings completely cover abdomen.
  • Chewing mouthparts.
  • Will fly on occasions.
  • Good gliders.
  • Will travel a long way from their breeding areas to feed.

 

Nymph (The Young):

  • Look similar to adult but wingless.
  • Greyish-brown in colour until later instars (moults) which become more like the adult colouring.

 

Life Cycle

Gradual / Incomplete metamorphosis (egg – nymph – adult). Eggs are encased in an egg capsule (Ootheca). Female carries egg capsule (Ootheca) up to 4 days then deposits the capsule near a food source, in crevices, on walls, or under workable material such as moist wood, so as to camouflage it. Eggs per capsule: 12-16 (in two rows). Incubation period: 38-55 days. Nymphal period: 160-971 days, 400 days (avg). Nymphs normally moult 7-13 times to reach adulthood. Females may produce 6-90 egg capsules in a lifetime. Adult lifespan: up to 2 years.

pests-germancockroachGerman Cockroach (Blattella germanica)

Structure, Appearance and Characteristics

Adults:

  • Approx. 12-16mm in length.
  • Pale brown with two longitudinal streaks on the pronotum.
  • Have wings but rarely fly.
  • Chewing mouthparts.
  • Nocturnal but may be seen during daytime if population is large.
  • High reproductive potential because of speed of life cycle and number of young in comparison to other species.
  • This presents an increased tendency for this species to become resistant to chemical through ‘selection’.
  • Very active.

 

Nymph (The Young):

  • Look similar to adult but wingless.
  • Darker brown, nearly black in colour.
  • A single light strip down the middle of the back is normally prominent.

 

Life Cycle

Gradual / Incomplete metamorphosis (egg ¡V nymph ¡V adult). Eggs are encased in an egg capsule (Ootheca). Female carries egg capsule (Ootheca) until eggs are ready to hatch. Eggs per capsule: 30-48. Incubation period (24„aC): 28 days (avg). Nymphal period (24 C): 40-125 days. Nymphs normally moult 7 times to reach adulthood. Females may produce 4-8 egg capsules in a lifetime. Adult lifespan: up to 1 year.