New Zealand Plant Protection 64 (2011): 282
Scaptomyza flava (Diptera: Drosophilidae), known as European leaf miner, has recently been identified as the pest species causing major damage to seed and other brassica crops grown in the South Island. This pest is particularly damaging to hybrid Asian brassica seed crops but is also a major pest of seedlings of radish, turnip and broccoli plants. A larval/pupal parasitoid, Asobara persimilis (Hymenoptera: Braconidae), is an effective natural enemy of S. flava at Pukekohe at certain times of the year. A project funded by MAF Sustainable Farming Fund involves mass-rearing the parasitoids in Auckland and releasing them in unsprayed brassica crops in Canterbury and North Otago. A total of 6550 pupae and 760 emerged adults were released over fortnightly periods at 4-6 sites from October 2010 to April 2011. The pupae included about 80% parasitised pupae and 20% that were unparasitised as a source of hosts for emerging parasitoids. Over-wintering surveys and further releases are planned for 2011/12 to try and establish this natural enemy as part of the ongoing development of IPM tools for seed, forage and vegetable brassica crops grown in the South Island.
Copyright © 2011 New Zealand Plant Protection Society (Inc.).