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Biocontrol introduction

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

Agent introduced: Alysia manducator (Hymenoptera: Braconidae)

Imported: 1926-1927

Import source: UK

Import notes: Cameron et al. (1989) - between November 1926 and January 1927 three consignments of blowfly puparia (species not recorded) arrived (5,050 in all) from which 232 A. manducator emerged. On receipt A. manducator was found to readily attack larvae of Lucilia sericata (common green bottle fly), Calliphora stygia and Chrysomya rufifacies (hairy maggot blowfly).

Released: 1926-1927

Release details: Cameron et al. (1989) - the first field liberations of unspecified numbers were made onto maggot-infested carcasses and offal at Blenheim, Canterbury, Weraroa (near Levin) and Kaitaia in 1926-27. Almost 150 releases were subsequently made over the whole country between 1928 and 1935 from Auckland to Central Otago.

Establishment: Cameron et al. (1989) - a series of reports (1935 - 1939) noted that A. manducator was well established and had spread naturally from the lowlands of Marlborough to the inland hill country.

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. A 1935 report notes that rates of parasitism by A. manducator in the field were never established, but a 1930 publication considered it to have a greater efficiency in the control of sheep blowflies than either Tachinaephagus zealandicus or Nasonia vitripennis. In a flystrike survey between 1984 and 1987, from over 600 samples of blowfly larvae, parasitoids were reared from only seven samples, but A. manducator was not among them. 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 A. manducator by T. zealandicus. Concern has also been expressed that N. vitripennis might interfere with A. manducator as it did in the United Kingdom. One factor that may limit the success of A. manducator is its reluctance to attack larvae in faecal matter.

Impacts on non-targets: Early (1984) - A. manducator "is known to attack European [Calliphora vicina], small blue [it is uncertain which species this refers to; perhaps Calliphora vomitoria], New Zealand blue [Calliphora quadrimaculata, a New Zealand native, an occasional flystrike blowfly], brown [Calliphora stygia, a target species], green [Lucilia sericata, a target species], and hairy maggot [Chrysomya rufifacies, a target species] blow flies." Cameron et al. (1989) - as well as the three target species, A. manducator has been recovered from C. vicina, C. quadrimaculata as well as representatives of the dipteran families Muscidae and Sarcophagidae.

References

Cameron PJ, Hill RL, Bain J and 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.