Stephen Goldson

New Zealand is a country built on its primary industries, on its ability to produce food not just for its own population, but also for much of the world.

However, NZ farmers increasingly have to contend with pests and diseases that can severely damage, or even destroy, their crops. Some of these agricultural pests are native (grass grub), while many others are accidental imports (Argentine stem weevil, clover root weevil).

In the pastoral sector alone, the annual impact of such insect pests is somewhere between $1.7 billion and $2.3b.

One way to deal with weeds, pests, and diseases is to apply synthetic pesticides. Indeed, this has been the default option in every farming sector for decades. However, synthetic pesticides rarely work well for long (pests develop tolerance) and they can damage our country’s unique environment.

They can also present health risks for farmers, staff, and neighbours, are becoming less socially acceptable, and their residues are increasingly unacceptable to our trading partners. These trading partners have access to ever-more sophisticated technologies that can detect many sorts of agricultural chemical residues, posing the risk of non-tariff barriers.

NZ’s trading success relies on its reputation for product safety and quality. But that reputation is under dual threat – from pests and diseases and, at the same time, from the increasing intolerance of synthetic pesticides.

We must find substitutes.

To protect our reputation, and our ability to trade, it is essential NZ develops acceptable and effective weed, pest, and disease suppression for all our farming sectors. The only way to do that is through scientific research.

Scientific research that may lead to new biocontrol options is the very reason for the Bio-Protection Research Centre’s existence.

Sometimes those biocontrol agents are predatory or parasitic insects that target the pest (such as parasitoid wasps that attack pasture weevils). But other times they are biopesticides – pest-control products based on live microbes and their associated metabolites.

For example, in the horticulture sector we have successfully developed Kiwivax, a product based on the Trichoderma fungus that helps to control PSA in kiwifruit. It is compatible with another new biopesticide being developed by Plant & Food Research (Aureo Gold), and even copper, and can be used to target different growth stages.

We have developed vineyard biocontrol based on planting Phacelia to support the parasitic insects that control pests, resulting in reduced pesticide use. Likewise, we have collaborated with AgResearch in implementing biocontrols for weevil pasture pests and understanding their ecology and genetics.

Bioprotection science is also becoming increasingly sophisticated and nuanced. It’s not good enough for bioprotection solutions simply to work – they also need to be socially acceptable. For example, much of BPRC’s research on kauri dieback involves working with Maori to understand their knowledge of these taonga and of forest health. And we are also working to understand Maori views on biocontrol.

Bioprotection onfarm is one thing, but another critically important part of NZ bioprotection must be improved biosecurity through detection and interception at the border, stopping pests and diseases before they become established.

Here again, fundamental science carried out by BPRC researchers and collaborators (including the multi-institute collaboration Better Border Biosecurity) is making a real difference.

In 2018, our scientists revealed they had adjusted a technique called stable isotope analysis to detect exactly where newly discovered pests had come from. Such information is crucial in understanding whether the pest is part of an established but previously undetected population or is a new incursion.

The challenges facing New Zealand’s farming sector are many and varied, and the threat of newly emerging or imported pests and diseases is just one of them. But it is a challenge for which we can grow our own solutions by continuing to invest in bioprotection science.

  • Professor Stephen Goldson is deputy director of the Bio-Protection Research Centre.