The 4th International Congress on Biological Invasions (ICBI2023) took place in Christchurch, New Zealand, between Monday 1 and Thursday 4 May, with a sharp focus on innovation, collaboration and partnership.
ICBI2023 offered attendees a unique forum in which to explore ideas, share knowledge and work collaboratively in the development of potential effective responses to the global challenges and threats posed by Invasive Alien Species (IAS).
In Australia, IAS present risks to the biodiversity, ecological systems and food security of our many and varied ecosystems, including our forests.
Strategies discussed during the event related to pre-border, at-border and post-border risks, with the latter needing effective, long-term pest management practices that won’t cause further or alternative damage to forests and wood products.
Biosecurity in Australia’s Forests across space, time and the biosecurity continuum
Dr Helen Nahrung, Senior Research Fellow at the University of the Sunshine Coast’s Forest Research Institute, and Dr Angus Carnegie, Senior Principal Research Scientist at the New South Wales Department of Primary Industries, gave a presentation titled ‘Biosecurity in Australia’s Forests across space, time and the biosecurity continuum’.
The presentation focused on their recently completed work to characterise the arrival, establishment, spread and impact of non-native insects and pathogens established in Australia’s native, amenity and plantation forests. This project was the first of its kind to be conducted in the country.
“Our aim was to better understand the ecological processes underpinning biological invasions and to link these historical arrivals with border interception frequencies, biological traits, commodities, and countries of origin, as well as to biosecurity mitigation measures,” Dr Nahrung told attendees.
“We also assessed recent forest-related insect and pathogen post-border detections and biosecurity responses, to identify factors that will lead to increased pest detection, and to provide information for prioritising future eradication attempts.
“Finally, we compared exotic insect species that are considered threats to Australia’s forests with already-established non-native species in terms of their biological and phylogenetic traits, border interceptions, origins and geographic distributions, to identify similarities between groups, and to assist with predicting future invasion events,” Dr Nahrung said.
The outcomes of this work included the development of a comprehensive database of non-native pests in Australia’s forests, the identification of patterns that facilitated invasions, the collection of data to support a national forest surveillance program, and a workflow that can be applied to other plant-based industries to improve biosecurity outcomes.
As a result of the momentum arising from the conference, Dr Nahrung and Dr Carnegie are now coordinating an Australia-New Zealand Forest Health and Biosecurity Working Party to discuss how research results and outcomes can most effectively be operationalised between to two countries.
Dr Nahrung stressed the importance of such proactive initiatives, given that Australia’s forestry industry faces significant challenges in ensuring its preparedness to meet existing, emerging and new forest health and biosecurity threats.
“Increasing trade and travel escalate the risk of exotic pests establishing in Australia, and climate change is predicted to affect the susceptibility of trees to pests, while also increasing the frequency and intensity of droughts and fires,” Dr Nahrung said.
“As the risks increase, Australia’s technical capacity in forest health and biosecurity is declining. This substantially weakens our ability to identify and respond to biosecurity threats, solve emerging forest health issues, and manage ongoing pest risks – all crucial for sustainable forest productivity and market access.”
Mitigating myrtle rust damage
Dr Anne Sawyer, a molecular plant biologist at The University of Queensland, gave a presentation titled ‘Double-stranded RNA as a novel control for myrtle rust’.
Myrtle rust is a plant disease caused by a highly invasive fungal pathogen, Austropuccinia psidii, which infects more than 480 Myrtaceae species, and is a major threat to natural ecosystems and native plant industries, including forestry.
Management of myrtle rust in nurseries and plantations relies on the use of clean planting material, treatment with chemical fungicides and the selection of resistant cultivars. However, these control strategies are not suitable for natural environments and growers are transitioning away from chemical pesticides.
Dr Sawyer and her team explored the use of double-stranded RNA (dsRNA) as an environmentally sustainable control for myrtle rust.
DsRNA has a similar structure to DNA but is made of ribonucleic acid and is generated in host cells during the replication of most viruses. It is quickly developing a reputation as an appealing alternative to induce pest and disease resistance in various plants.
The researchers applied a pathogen-specific variant of dsRNA to a number of host plants to trigger RNA interference (RNAi) and silence the targeted myrtle rust pathogen genes, with promising results.
“Our findings indicated that dsRNA targeting essential genes has the potential for broad use in the management of the disease across natural and agricultural systems alike,” Dr Sawyer told delegates.
This work was conducted in collaboration with the Queensland Government’s Department of Agriculture and Fisheries.
Evaluating pest risk to timber-in-service
In other biosecurity news, Dr Nahrung attended the 54th International Research Group (IRG) on Wood Protection meeting in Cairns and presented the results of a recent collaborative review of timber-in-service pests in Australia.
Timber-in-service refers to wood prepared for use in building and carpentry, as well as other wooden infrastructure such as bridges, pylons and power poles.
Certain pests such as bostrichid borers and termites pose a risk to timber-in-service materials throughout their entire service life. The impacts include significant damage, as well as high prevention and control costs associated with timber structures.
The review, which was published in Australian Forestry, set out to identify native and non-native insects associated with timber-in-service in Australia, their impacts and current management practices.
It found more than 25 non-native insect species in the Bostrichidae, Ptinidae, Cerambycidae and Kalotermitidae families, and at least 12 non-native timber decay fungi, all of which have accidentally been introduced and established in Australia, with 17 found to have moderate to high impact to timber-in-service products.
While strict pre-border and at-border biosecurity regulations exist to help reduce entry of insects in timber, timber products and wood packaging, timber-in-service pests are not covered by any specific post-border biosecurity arrangements in Australia like pests that impact living trees are.
As a result, the forestry and wood products industry is unable to effectively participate in decision-making around how new incursions of timber-in-service pests are dealt with.
Recommendations made by the authors resulting from this review include:
- the need for a systematic review of current pests
- efforts to address the loss of research and surveillance capacity for forestry, including timber-in-service
- better risk modelling, including evaluation of current control measures against future pests
- improved clarity around the role of the forestry and wood products industry in responding to new detections
- stronger relationships between biosecurity surveillance agencies
- pest controllers and researchers.
These efforts can be further strengthened by increased engagement with householders on how to reduce the likelihood of reduced service life through pest infestation.
