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
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.
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