NZ: Critics say new biological hothouse pest-control is danger to NZ plants and insects

A bug tomato growers want to introduce to control hothouse pests is a danger to New Zealand plants and insects, critics say. Commercial fresh-tomato growers, Tomatoes NZ, want to introduce the bug to reduce their use of pesticides in hothouses, especially the white butterfly.

Tomatoes NZ asked the Environmental Protection Authority (ERA) in November to allow the insect macrolophus pygmaeus to be imported and released into greenhouses.

The ERA is now considering the request and submissions opposing the introduction of the bug.

The growers say it will feed on a wide range of greenhouse pests including whitefly, mites, thrips, aphids and leafroller, and say the bugs are considered effective as a bio-control in hothouses overseas.

The bugs, which have a particular fondness for white butterfly eggs, larvae, pupa and adults, also suck the juice out of plants as well as eating pests.

Growers are looking for more biological controls, as consumers demand lower pesticide use in commercial production worldwide, but still perfect-looking fruit. Pests are also developing resistance to insecticides.

There are about 150 growers in New Zealand who export 40,000 tonnes of fresh fruit, mainly to Australia, with most grown year-round in greenhouses. The industry is worth about $120 million annually.

The growers' group said the insect would be critical for the long-term viability of the tomato sector, reducing reliance on chemicals with benefits for the environment, consumers and growers.

While the growers' efforts to reduce chemical use have been praised by many of those opposing their application, the opponents say the risks to native insects and plants should they escape, is too great.

"The most reliable climate modelling shows macrolophus pygmaeus would have optimal ecoclimate conditions to establish in Northland, Auckland and the east coast of the North Island, and suitable conditions extend south to Nelson," University of Auckland biosecurity lecturer Dr Margaret Stanley said.

"There is a risk some New Zealand native species will be lost if this application is approved, or at the very least there will be irreversible damage to plant and invertebrate animal communities.

"While the industry's drive to reduce the use of chemical sprays is admirable, the likely negative consequences for New Zealand are likely to be worse than the current spray regime."

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