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Biocontrol introduction

Target pest: Calliphora stygia (Diptera: Calliphoridae), brown blowfly

Agent introduced: Tachinaephagus zealandicus (Hymenoptera: Encyrtidae)

Imported: pre 1927

Import source: Australia

Import notes: Cameron et al. (1989) - a 1927 publication reported that four blowfly puparia said to contain T. zealandicus had been obtained from Australia. No other records of subsequent introductions have been found.

Released: Unknown

Release details: Cameron et al. (1989) - no details of releases have been found; some may have taken place as a 1930 publication stated that T. zealandicus occurred in greater numbers than the introduced parasitoid Nasonia vitripennis.

Establishment: Cameron et al. (1989) - a 1930 publication stated that T. zealandicus occurred in greater numbers than the introduced parasitoid Nasonia vitripennis. The basis for this quantitative assessment is not given though T. zealandicus was said to be interfering with the introduced parasitoid Alysia manducator, so some recoveries must have been made. It is possible that T. zealandicus was already present in New Zealand, either as a native or as the result of an earlier, unrecorded introduction.

Impacts on target: Early (1984) - nothing is known of the effectiveness of introduced parasitoids in reducing either blowfly populations or flystrike on sheep. Cameron et al. (1989) - as flystrike continues to be a significant problem in New Zealand the overall effects of parasitoids have presumably been minimal. In a flystrike survey between 1984 and 1987, from over 600 samples of blowfly larvae, parasitoids were reared from only seven samples. Percentage parasitism (assessed in only four cases) ranged from 4.2% to 20.0% in the samples received. The preponderance of T. zealandicus (accounting for five of the seven samples from which parasitoids were reared) may support the suggestion of interference of the introduced parasitoid Alysia manducator by T. zealandicus.

Impacts on non-targets: Early (1984) - T. zealandicus attacks a range of calliphorids and muscids and can also develop on braconid primary parasitoids. Cameron et al. (1989) - as well as the main flystrike species C. stygia and Lucilia sericata, T. zealandicus parasitises Calliphora vicina and the native C. quadrimaculata (an occasional flystrike blowfly).


Cameron PJ, Hill RL, Bain J, Thomas WP (1989). A Review of Biological Control of Invertebrate Pests and Weeds in New Zealand 1874-1987. Technical Communication No 10. CAB International Institute of Biological Control. DSIR Entomology Division. 424p.

Early JW. (1984). Parasites and predators. Chapter 16, New Zealand Pest and Beneficial Insects. Ed. R.R. Scott. Lincoln University College of Agriculture, 1984. 373 pp.