New Zealand scientists oppose biocontrol import

New Zealand scientists are lining up against tomato growers who want to bring in a new bio-control to help them deal with a destructive pest in green-houses.

Industry body, Tomatoes New Zealand wants to import and release a predatory mirid, Macrolophus pygmaeus, to control whitefly, which damages tomatoes and related crops such as eggplants, cucumbers, and capsicums.

The New Zealand Environmental Protection Authority is hearing the case for and against the proposal at Pukekohe. The authority has received more than 30 submissions, mostly from growers supporting the proposal.

They say whitefly cause direct damage by sucking plant juices, stunting growth, causing wilting and reducing crop yield. Heavy feeding by whitefly can eventually kill plants.

In New Zealand, whitefly is currently controlled by the use of chemical sprays and also one biocontrol already available, a parasitic wasp Encarsia formosa. But growers say it doesn't provide adequate control of whitefly on its own. They want more choices for controlling the pest and say Macrolophus pygmaeus, is effectively used overseas.

However, opponents, including insect and biosecurity scientists, farm foresters and a local body say there are too many risks in allowing the release of the mirid. They say it's highly unlikely it could be contained in green houses and it could establish wild populations, threatening a wide range of other non-targeted species, including native insects. Because of that, it has the potential to disrupt other biocontrol programmes for pests and weeds.