Jessica Lye 
Andie Wong
It’s a pest that can aggregate in the hundreds, or even thousands. It has a ravenous appetite for fruits and vegetables, and it just loves to share your house in the colder months.
It is the brown marmorated stink bug, an exotic pest that is spreading around the globe. Catching wind of an outbreak early can mean the difference between these bugs making themselves at home, or eradication.
Read on to find out how an innovative detection technology could become a fast and effective tool for catching this bug at the border.
How much of a biosecurity risk is BMSB?
An economic pest, the brown marmorated stink bug (BMSB: Halymorpha halys) is native to China, however over the past 15 years spread and establishment of the pest to other continents has steadily increased.
This rapidly growing international biosecurity threat is known to ‘hitchhike’ by hiding and hibernating in vehicles, machinery, cargo or shipping containers. Due to strong trade links with the USA and Italy, the hitchhiking behaviour enables BMSB to arrive at New Zealand and Australian ports via cargo ships at certain times of the year.
The impact of BMSB establishment in Australia and New Zealand would vary depending on the point of entry; however it is well demonstrated that this bug can survive on a wide range of fruits and vegetables, and has a strong ability to spread long distances through flight dispersal or as an inadvertent hitchhiker (Funayama, 2004).
Feeding damage will impact on product aesthetics as well as yield. In the US, all life stages of the bug have been found to survive on grape, with as little as five BMSB feeding per cluster leading to a 37% yield decline (Smith et al. 2014). Volatile compounds produced by BMSB, including tridecane, dodecane, trans-2-decenal and trans-2-undecen-1-ol can significantly taint wine and juice (Mohekar, 2016).
The importance of fast and accurate pre- and post-border diagnostic tools
A sensitive, accurate diagnostic test and sampling protocol for BMSB has the potential to aid border surveillance efforts, as well as incursion response activities should the bug be intercepted outside of Australian ports.
Plant pest biosecurity incursions in Australia and overseas highlight the importance of fast diagnostics during a pest incursion and the impacts of misdiagnosis in regard to time lost on launching a response.
As an example, Spotted Wing Drosophila (Drosophila suzukii) hit the headlines in 2009 following reports of unusual damage to a range of soft fruits in California, USA. Damage had been observed the previous year, but the belief that this was an endemic species of Drosophila attacking damaged or over-ripe fruit led to a delay in action being taken.
When the pest was accurately identified it was realised that this was a significant exotic pest. However, by the time an accurate identification had been made it was too late to consider eradication.
How can we speed up reliable detection?
In a novel application of environmental DNA (eDNA), a new research and development initiative, led by cesar and undertaken in partnership with EnviroDNA and Plant and Food Research New Zealand, is developing eDNA based diagnostic technologies to detect BMSB at border points and in agricultural regions.
Environmental DNA (eDNA) is an innovative species detection tool being used in Australia and overseas for a range of activities in the fields of biosecurity, biodiversity conservation and environmental impact assessments. All organisms leave traces of their DNA in their surrounding environment and this technology now makes it possible to take environmental samples to determine what species were present in real-time.
These molecular techniques detect trace amounts of DNA, potentially increasing the detectability of biosecurity threats, and are therefore an exciting prospect for integration into biosecurity activities to prevent incursions and also delimit outbreak areas.
In this project, we will develop and validate eDNA based assays and sampling protocols for the real-time detection of BMSB at ports and in the field to increase the sensitivity and cost-efficiency of detection of this species in biosecurity activities. The eDNA methods and assays will be field-tested as part of a collaborative project with Plant and Food Research New Zealand in an outbreak area such as Santiago, Chile, with sensitivity and cost-efficiency modelling used to determine optimised sampling protocols for Australia (and New Zealand).
Environmental DNA research overseas has shown how eDNA is a more sensitive approach for detecting BMSB than other detection methods (Valentin et al. 2018). In this project we will build on this research to establish eDNA as a key detection tool for BMSB surveillance and outbreak activities in Australia and New Zealand.
Environmental DNA technology has never before been used in Australian horticulture as a surveillance tool for exotic pests. Once ground-truthed for use in biosecurity surveillance, the potential for use of eDNA surveillance technology in agricultural industries is high. For instance, it may be applied by horticulturalists for purposes outside of biosecurity (eg. food safety/quality assurance).
A key outcome of this project will be improving awareness of BMSB and eDNA technology among biosecurity personnel and industry development officers through the development of education material and on the ground training. This project will also include awareness activities for BMSB preparedness within the Australian wine industry.
The project will put eDNA technology through its paces as a cost-effective method for quickly delimiting an outbreak of BMSB in production zones, as well as using the testing method for screening imported goods from high risk pathways.
Acknowledgements
AS19000 ‘Novel technologies to assist rapid and sensitive detection of Brown Marmorated Stink Bug’ includes funding from Australian agricultural industries through the Hort Innovation Hort Frontiers fund and Wine Australia, with in-kind and cash investments from project partners.
This article draws on findings from:
Fraser, D., Kumar, S., and Aguilar, G. (2017) Mapping the Potential Global Range of the Brown Marmorated Stink Bug, Halyomorpha halys, with Particular Reference to New Zealand. Climate 5: 75
Funayama, K., (2004) Importance of apple fruits as food for the brown marmorated stink bug, Halyomorpha halys (Stål) (Heteroptera: Pentatomidae). Applied Entomology and Zoology. 39: 617623.
Mohekar, P. (2016) Brown Marmorated Stink Bug (BMSB), Halyomorpha halys Taint in Wine: Impact on Wine Sensory, Effect of Wine-processing and Management Techniques. Dissertation Oregon State University.
Cover image: Photo by Susan Ellis, Bugwood.org, CC BY 3.0 US
