Black field cricket

Scientific name: Teleogryllus commodus
  • Key characteristics
  • Biology
  • Impacts
  • Control
  • Further information

  • Black crickets are found throughout the North Island and milder coastal regions of the South Island
  • Usually they are only economically important in Northland, Auckland, Waikato, Bay of Plenty, Hawkes Bay, Taranaki and Manawatu
  • They are often confused with several species of much smaller native crickets.

  • 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 and although they generally do not fly there are occasional mass flights when numbers are high. Females have a long ovipositor (egg-laying tube) which extends past and under the wings. The adult males “chirp”, by rubbing their wings together
  • There is just one generation a year but the life stages overlap. Eggs, which are white, ovoid-shaped, and about 0.3 cm long are laid singly, but loosely clustered, about 1 cm deep in damp soil. A single female cricket is capable of laying up to 2000 eggs between mid-February and early May. After hatching the nymphs take 2-4 months to mature into adults and then live for 2-3 months. The nymphs pass through 9-10 stages and resemble small adults but do not have wings, or in the case of females, ovipositors, until the 8th and 9th stages. Overwintering occurs as eggs. The smaller nymphs live and hide within pasture and this makes them difficult to detect. Larger nymphs and adults tend to shelter in cracks in soil or under cow pats and litter
  • Although found throughout the North Island and milder coastal regions of the South Island they are usually only economically important in Northland, Auckland, Waikato, Bay of Plenty, Hawkes Bay, Taranaki and Manawatu. Black field crickets, especially the nymphs, are often confused with several species of much smaller native crickets. These only grow to about 1 cm and crickets larger than this are likely to be black field crickets. Native crickets are also active during the day and when disturbed will jump and be easily seen. In contrast black field crickets are active at night and if disturbed during the day will run for shelter and remain hidden. When threatened they will jump quickly away. Black field crickets can also be identified by a distinctive white band around their middle.

Impact on pasture

  • Black field crickets are generally pests only in northern areas of New Zealand. Their significance is increased in long dry periods and in soils that crack in during these periods. They feed most commonly on the leaves and germinating seeds of grasses, especially ryegrasses, but also eat legumes and weeds
  • Their feeding, and the type of damage they cause, can be categorised into three types:
    1. Grazing, where adults and the larger nymphs compete with stock for food. Over one hectare 2 crickets/m2 will consume the equivalent of one sheep. In plague seasons as many as 20-40 crickets/m2 frequently occur and can cause losses of 30kg DM/ha/day. In dairy pasture an average density of 25 crickets/m2 can be responsible for 2000 kg DM/ha/yr lost production
    2. During long dry periods the growing crowns of grasses are attacked often killing the plants and leaving the soil open to weed invasion
    3. Sown, or self sown seedlings, may be destroyed by cricket feeding.
  • The potential for long term pasture damage and unseen losses makes early detection of crickets important. In areas prone to cricket damage the density can be quickly assessed by pouring a weak detergent solution (4 mls dishwashing liquid in 10 L water) over a known area of pasture. This will “flush” crickets out of cracks in the soil and make it easy to count them and determine their density. A density of 10/m2 is considered economically damaging.

Chemical control

  • Populations of more than 10 crickets/m2 are economically damaging. Control of black field crickets is usually by using grain baits coated with an insecticide (maldison). For more information consult the New Zealand Agrichemical Manual or an agrichemical company representative.