The damage potential of the black field cricketTeleogryllus commodus

Abstract

Regressions of herbage loss on population density of black field cricket (Teleogryllus commodus Walker) (Orthoptera: Gryllidae) were obtained by caging different life stages at a range of densities over ryegrass (Lotium perenne )-white clover (Trifolium repens)-dominant pasture. Significant (P<O.OOl) relationships between herbage loss and insect density were found only in trials involving adult crickets. The different life stages used markedly affected the slope of the regression of herbage loss on cricket density. The early adult stages caused the greatest herbage loss, large nymphs and late adults were intermediate, and the small nymphs caused the least loss. A field population of five crickets per m 2 , which was regarded as low, was estimated to cause pasture loss of 1.8 kg. ha-1.d-1 of dry matter (DM) , a grazing pressure equivalent to 1.5 ewes per hectare per day. A field population of 60 adult cricket per m 2 , which is regarded as high, was estimated to cause pasture loss of 25.1 kg. ha-'.d-1 ofDM (equivalent to 21 ewes per hectare per day) and the same population over all stages throughout one summer, a total seasonal pasture loss of 2920 kg. ha-1 of DM. These results show that black field crickets cause considerable pasture losses at all developmental stages, and should be controlled as early as possible each year to reduce pasture loss and damage.

Insect damage to grasses oversown into tussock grassland in Central Otago, New Zealand

“…All three carabids consumed grass seeds readilyin captivityand caused damage similar to that observed in the field, and Nemobiine crickets are well-known as granivores (McIntyre 1969). Both carabids and crickets have been implicated in seed theft elsewhere(e.g., Blank & Olson 1981;Forsythe 1982).…”

Screening sixteen pasture species for tolerance to attack by black field cricket (Teleogryllus commodus)

“…Paspalum (Paspalum dilatatum Poir.) has been considered resistant (Banfield & Cottier 1948;Blick 1959), whereas cocksfoot (Dactylis glomerata L.) and white clover (Trifolium repens L.), although eaten by crickets, may recover to dominate pastures (Blick 1959;Blank & Olson 1981). Kikuyu grass (Pennisetum clandestinum Hochst.)…”

Two egg parasites (Hymenoptera: Scelionidae) of the black field cricket,Teleogryllus commodus(Orthoptera: Gryllidae), in New Zealand

“…The black field cricket, Teleogryllus commodus (Walker), is a pasture pest of considerable importance in New Zealand, especially in Northland and Auckland-districts (Blank & Olson 1981). It is also a problem in Australia (Browning 1954), and appears to be widely distributed throughout the Pacific (Kevan 1965).…”