Supreme science award for pest-fighting pioneer

AgResearch emeritus scientist Stephen Goldson.

A long-serving scientist who took the fight to pasture pests in New Zealand and reaped huge benefits for the country has won the highest honour at the 2023 Science New Zealand Awards.

AgResearch emeritus scientist Stephen Goldson was recently named the Supreme Award winner in recognition of a career in which he and his team found a way to control pasture-consuming weevils costing the country hundreds of millions of dollars a year.

Dr Goldson led the identification and introduction to New Zealand of wasps that are the natural enemies of the lucerne, Argentine stem and clover root weevils. The “parasitoid” wasps proved highly effective in seeking out the weevils and killing or sterilising them by laying eggs inside the pests.

The judges said Dr Goldson stood out among the finalists for the economic and environmental benefits of his work “and the excellence of his research sustained over a long period of time”.

The arrival of these weevils on New Zealand’s shores decades ago “ripped the pasture to shreds many times”, Dr Goldson says.

“It was problem insecticides weren’t able to deal with, for many reasons. These pests together were costing about $400 to $500 million a year to the primary industries. We had three weevil pests and we’ve suppressed them all, using natural enemies we’ve brought in from where these pests came from.”

Dr Goldson described it as “one chance in a thousand” to get a good result from the effort of introducing the wasps.

“It was a long-term project. It was expensive and very risky, and it worked. And without teamwork, this couldn’t have been done.”

In addition to the wasps reducing the lost production from depleted pastures, they have also had the effect of reduced insecticide use and environmental impacts that those chemicals can entail.

Despite the successes in suppression of these pests, Dr Goldson has more recently led research showing that the weevils are beginning to evolve resistance against the introduced wasps. This has added urgency to develop new environmentally friendly methods to counter the pests.

Work is now underway in conjunction with the University of Otago to look at the genetics of biocontrols such as these wasps to figure out how to maximise their reliability and efficiency.


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