Biocontrol introduction

Target pest: Mayetiola destructor (Diptera: Cecidomyiidae), hessian fly

Agent introduced: Platygaster hiemalis (Hymenoptera: Platygastridae)

Imported: recorded before 1893 but was reintroduced 1894, possibly also 1894/5

Import source: Self imported pre 1893, 1894 England

Released: 1984

Release details: Released near Masterton and possibly Marton in the North Island and Milburn and probably Milton (both Otago) in the South Island.

Establishment: Cameron et al. (1989) - known to be present in Mid Canterbury but distribution otherwise unknown. Prestidge (1992) - present in Waikato. Withers et al. (1995) - not present in Hessian fly pupae collected from Waimate (South Canterbury); present in pupae collected in Manawatu.

Impacts on target: Prestidge (1992) - Waikato: pupal parasitism of Hessian fly Jan-Mar 1988 and 1989 was 26-42% and 3-34% respectively. Ninety-two percent of these incidences of parasitism were caused by P. hiemalis. Wiithers et al. (1995) - Manawatu: first and second post-winter generations of Hessian fly pupae had 5% and 15% P. hiemalis parasitism respectively. However, although the parasitoid increased in abundance over summer it did not prevent increases in Hessian fly populations.

References

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.

Prestidge RA. (1992). Population biology and parasitism of Hessian fly (Mayetiola destructor) (Diptera: Cecidomyiidae) on Bromus willdenowii in New Zealand. New Zealand Journal of Agricultural Research 35: 423-428

Withers TM, Harris MO and Davis LK. (1995). The incidence of Hessian fly and other pests in New Zealand wheat crops. New Zealand Plant Protection 48: 165-169