Black Field Cricket

Adult black field crickets are about 2.5 cm long and are actually dark brown. They have large heads with very long antennae. They have wings although they generally do not fly. The adult males “chirp”, by rubbing their wings together.

Black field crickets are normally a problem only in Northland, Auckland, parts of Taranaki, and Hawke’s Bay. Eggs are laid in moist soil from February to May, and nymphs (immature adults) emerge from November to January. Adults appear from February and live for two or three months.

They inhabit cracks in the soil and eat surrounding crowns of grasses, which usually die. During long drought periods the growing crowns of grasses are attacked; this often kills the plants and leaves the soil open to weed invasion.

When numbers grow large they can often invade homes becoming a nuisance pest.

Note: Over the past year the tropical house cricket (Gryllodes sigillatus) has been found in several different locations in the Tauranga airport area. It is known to cause very little or no damage to plants. It can, however, become a "nuisance pest" when it enters houses and can be treated in the same way as the black field cricket.

The tropical house cricket is 12 – 22 mm long and light yellowish-brown coloured. The sexes are easily distinguished as adults: all males have short wings used for acoustic signalling that cover half of the abdomen whereas females are wingless and have a functional ovipositor for laying eggs into the soil.

It is not necessary to report findings of the tropical house cricket to MPI as the investigation has finished.