Dr Rebecca McDougal is part of a Scion team at the leading-edge of understanding complex tree diseases that are threatening to wipe out a national taonga.
New Zealand boasts a constellation of rising female scientists helping restore gender balance to the field and communicating with the public in ways non-scientists can relate to. Doctors Siouxsie Wiles and Michelle “Nano-girl” Dickinson were helping communicate complex and pressing science issues well before covid came along. Added to this universe of talent is Dr Rebecca McDougal, a Scion forest pathologist, biosecurity award finalist, and Farmers Weekly land champion. She spoke to Richard Rennie.
Growing up on the Central Plateau, Dr Rebecca McDougal was never far from a pine tree and it was a primary school project that first sparked her interest in the ubiquitous flora.
Today she is part of a Scion team at the leading-edge of understanding complex tree diseases that are threatening to wipe out a national taonga and seriously damage a valuable export crop.
Her particular area of expertise is around molecular forest pathology, focusing upon plant pathogens and most recently Phytophthora pluvialis.
Like pine trees, the plant damaging water moulds are plentiful and they affect multiple plant species.
Despite 170 species of phytophthora being discovered between 100-500 are still thought to be out in the ether, yet to be identified.
For NZ foresters, P. pluvialis, or red needle cast, was first seen in 2008 and is carried through pine forests in airborne water droplets, causing pine needles to turn yellow, then red and then be blown away months later.
In a bad year it can cause a 40% loss of productivity in a forest, stunting tree growth until infected needles grow back. So far it is only found here, Oregon and more recently the UK.
“Whether it is climate change, or our ability to better detect them, Phytophthora are becoming more prevalent,” McDougal said.
With thousands of hectares of forests vulnerable to infection, a rapid diagnostic tool has been vital for detection, and McDougal has been instrumental in developing leading-edge molecular techniques to help determine the species affecting forests.
“Trees are not like kiwifruit or vineyards where they can be replaced and return to production in a short time, there are huge benefits to industry to identify infections early,” she said.
Early indications are that copper treatments can prove useful in controlling the cast’s spread, a control already applied in some areas for other diseases.
In the meantime, her work has also focused on dealing with a crisis visited upon one of NZ’s most sacred taonga, kauri dieback disease.
It is made more complex to detect due to it sometimes taking years for trees to exhibit visible signs of disease.
Scientists are hoping to find disease resistant trees in the natural population, and encouragingly the infection appears to vary across different kauri populations.
Her work here has studied the interaction between Phytophthora, the tree, and the soil to find opportunities to disrupt the interaction between the three.
As New Zealanders launch into an era of mass tree planting, both natives and exotics, McDougal’s work is also focused on nurseries. She is working with partners to develop a bio-secure system for plant movement that will ensure damaging pests and diseases are not included in the growing deliveries.
Invasive myrtle rust is a recent disease that has had some of its passage around NZ secured by way of nursery transfer, with some tree species now under threat from its spread.
“It would be very rewarding to see such a system get up and running here. We have seen in the United States how restoration projects have devastated local tree numbers due to diseases being transferred in with the project,” she said.
As the world wrestles with a disease arguably as tough to manage as the elusive Phytophthora, McDougal believes NZ’s biosecurity system has stepped up to the challenge that greater travel and trade has brought to our borders.
“We probably spend a lot more than other countries, but we also know we have a lot at stake. I have been very fortunate to be part of a team involved in it,” she said.
Meanwhile, her ability to speak across a spectrum of scientific understanding is helping maintain trust in science at a time when social media has made many supposed experts cast doubt upon conventions of research, science and discovery.
McDougal was nominated by the Forest Owners Association for innovation and communication in forest biosecurity, winners of the NZ Biosecurity Awards will be announced in February.
