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New weapons in the battle for urban biosecurity


20 September 2018

With over 10,000 reports of suspected new pests and diseases in New Zealand every year. It’s no surprise that our urban environments are being impacted.

Dr Tara Strand, Dr Steve Pawson, Dr Eckehard Brockerhoff and Dr Brian Richardson from Scion explain how they’re finding new ways to manage urban biosecurity incursion responses.

“Managing pests and diseases in a densely populated urban environment presents an array of challenges that will grow as urban migration continues and international movement of cargo and passengers increases,” says Dr Tara Strand.

“Our project researchers are developing tools and concepts that could result in faster detection of new organisms, reduced use of pesticide, improved incursion responses and engagement with communities, creating a stronger biosecurity defence network for New Zealand”, Tara explains.

Active surveillance using unmanned aerial vehicles

Understanding where a pest has come from and where it’s spread to can influence the response to a pest and early detection enables eradication treatments to prevent further spread.

Dr Steve Pawson and the team have been undertaking research trials to see if using UAVs (unmanned aerial vehicles) could detect pests earlier.

“Our trials have proven that UAV’s wired with a pheromone sensor-antennae can definitely detect specific pheromones from a target insect. We’re working with experts from France to miniaturise the concept and refine it,” says Steve.

Tara explains, “This tool is being further developed to pinpoint a pest’s location quicker than a human surveillance team. Time saved could reduce the opportunity for the organism to spread, minimise the treatment area and result in less disturbance to urban residents. It’ll also increase the chance of eradication; or help us to arrive at a decision point sooner than would otherwise be the case.”


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Targeted application for more efficient use of pesticides

Once we know how far a pest has spread, the next step is to eradicate it. For pest insects, current practice is often to treat the host plant, either by pesticide application or host removal, leaving the pest population to decline from loss of useable habitat, or by direct action of the toxicant.

Dr Ecki Brockerhoff and his team have created a model that links the pattern and amount of host plants across a landscape with the population dynamics of pest species. He explains, “The model looks at the distribution of host plants across the landscape and the effects on the target pest’s population, identifying how many and which host plants will need to be made unavailable to the pest species to drive it towards eradication.

"This new knowledge will help to develop new early incursion response strategies and more efficient use of controls like pesticides.”


Turning these targeted strategies into action, researchers are developing tools that deliver pesticides to a single tree at a time. Working with the company HeliResources, Dr Brian Richardson and the team have evaluated a ring-shaped spray boom that is tethered below a helicopter and delivers pesticide to one tree at a time. A working protocol for this new tool has already been delivered to the Ministry for Primary Industries (MPI) and is ready for deployment.

UAVs are also undergoing testing for targeted spraying. Machines tested to date are capable of delivering 10-20 litres of spray in a single load.

Brian says, “Broadcast spraying techniques are generally a last resort in urban environments, but the methods we’re developing will focus the control spraying where it’s needed, minimising unneeded disturbance.”

Evaluating engagement

Tools to improve community engagement in urban biosecurity issues are also being investigated by the research team. Together with MPI and Will Allen and Associates, researchers have developed a ‘rubric’ or framework to help biosecurity managers to visualise and measure the performance of their community engagement strategies.

As a tool, the rubric can help users learn and share from differing perspectives, measure social and technical details, quickly identify improvements required and is adaptable across programmes. A detailed rubric has been developed with MPI’s general surveillance team.

Tools for tomorrow

This short (three year) research programme has contributed new tools that are ready for deployment (vegetation fragmentation modelling, ring boom spraying procedures, general surveillance rubric) and their success has earned the programme a gold rating from funding provider, MBIE.

The research team credits the shared perspectives from industry bodies, Māori, regional councils and government departments for making this programme robust and relevant to the challenges of urban biosecurity, as well as the strength of national and international resesearch collaborations helping to realise these concepts.

“It’s not over yet,” says Brian, “This programme has helped us to test concepts and identify areas that we can improve on. We want to hone in on these next and will continue to develop and refine these tools.”