David Cook

Grapevine phylloxera Daktulosphaira vitifoliae Fitch (Hemiptera: Phylloxeridae) has been present in Australia for almost 150 years but has not spread to south-west Western Australia, in part due to the relative isolation of the region. Recent improvements in tourist access, with interstate flights now arriving at Busselton Margaret River Airport, raise concerns about potential phylloxera introductions via wine tourism. In this paper, we simulate the potential economic impact on the Western Australian winegrape industry following a hypothetical arrival event in the Margaret River wine region. We use soil texture maps to assess the suitability of winegrape-growing areas to phylloxera establishment and construct a model to predict the likely cost and revenue implications of replanting vines to resistant rootstock as they become infested. Our results suggest that if strict quarantine measures to limit spread are not implemented, a phylloxera incursion could affect 60%–70% of vines and cause cumulative losses of AUD150–290 million over a 50-year period. This is equivalent to a 3%–6% annual contraction of winegrape production.

Mobile phones have become essential tools for health care workers around the world, but as high touch surfaces, they can harbor microorganisms that pose infection risks to patients and staff. As their use in hospitals increases, hospital managers must introduce measures to sanitize mobile phones and reduce risks of health care-associated infections. But such measures can involve substantial costs. Our objective in this paper was to consider two mobile phone risk mitigation strategies that managers of a hypothetical hospital could implement and determine which involves the lowest cost. The first strategy required all staff to sanitize their hands after every contact with a mobile phone. The second involved the hospital investing in ultraviolet-C-based mobile phone sanitization devices that allowed staff to decontaminate their mobile phones after every use. We assessed each intervention on material and opportunity costs assuming both achieved an equivalent reduction in microbe transmission within the hospital. We found that ultraviolet-C devices were the most cost-effective intervention, with median costs of approximately AUD360 per bed per year compared to AUD965 using hand hygiene protocols. Our results imply that a 200-bed hospital could potentially save AUD1–1.4 million over 10 years by investing in germicidal ultraviolet-C phone sanitizers rather than relying solely on hand hygiene protocols.

1. Following the discovery of polyphagous shot hole borer Euwallacea fornicatus (Eichhoff) in Western Australia in September 2021, we estimated the likely economic damage that will result in the coming decades and the return on investment in eradication.

2. A bioeconomic model was used to simulate the insect's spread and economic impact based on additional urban and commercial tree management costs. Two scenarios were examined, one in which an eradication policy response was initiated, and one in which it was not.

3. With no eradication response, results indicated that median costs would reach A$6.8 million per annum in 30 years, with 98% of these costs relating to management in urban forests.

4. We conclude that the eradication funding currently proposed, involving an investment of A$45.0 million over 3 years, will not generate sufficient benefits to offset costs in the short-term, but may produce net benefits in the longer term.

Polyphagous shot hole borer Euwallacea fornicatus Eichhoff was detected in Western Australia in September 2021, and an eradication campaign funded by the Commonwealth government is underway. As part of contingency planning, we examined the cost effectiveness of alternative control strategies that could be used to mitigate urban forest impacts and maintain the benefits of trees to the local communities if eradication was not feasible. At the time this work was undertaken, decision-makers were concerned about the potential need to replace all urban trees susceptible to attack. We considered this strategy alongside less destructive strategies and assessed their cost effectiveness in terms of material and labor costs and the loss of ecosystem services resulting from reduced tree foliage. Using a stochastic simulation model, we found that a strategy that involved pruning necrotic limbs and treating trees biennially with systemic insecticide was almost always more cost effective than removing infested trees and replanting to resistant varieties. We estimated this strategy would cost A$55-110 million over 50 years, while tree removal would cost $105-195 million. A third strategy using a mix of chemical suppression and tree removal was also considered in light of new information about the pest’s host preferences. With an estimated cost of $60-110 million, this strategy was only slightly more expensive than using chemical suppression alone and could actually lead to eradication if the host range is as narrow as recent survey data suggests.

The World Trade Organization is not explicitly in the business of environmental protection, but through recent initiatives it has sought to better understand the complex relationship between trade and the environment and its role in promoting sustainable trade growth. In line with these initiatives, this paper discusses ways it might explicitly consider ecosystem services impacts when ruling on trade disputes so as to internalise ecosystem services externalities. We propose a change to existing methods of settling trade disputes to include a comparison between the traditional gains from trade and the multilateral change in ecosystem services associated with trade by incorporating a penalty system into the dispute resolution process. If this comparison assesses damages to ecosystem services to exceed the gains from trade then the penalty system suggests trade should not be allowed to take place. This penalty system in turn can create an incentive for exporting countries to reduce their impacts on ecosystem services to facilitate trade.

Following the detection of fall armyworm Spodoptera frugiperda (J.E. Smith, Lepidoptera: Noctuidae) in Western Australia in early 2020 and the lack of government response action, we estimate the impact it is likely to have on the state’s agriculture. A bioeconomic model is used to estimate cost and revenue implications for broadacre cropping and horticulture industries. We assume permanent S. frugiperda populations are likely to establish in areas of the state’s north and mid-west over the next decade, and other regions may experience sporadic outbreaks over single seasons. Over 0.8 million hectares of host crops could be permanently affected, while sporadic outbreaks may affect a further 150,000 hectares. Expressed in Australian dollars (A$), S. frugiperda is likely to add a A$14.2–39.3 million burden to agricultural producers per annum by year 10 of the outbreak. Approximately 55% of these damage costs are attributable to yield loss and 45% to increased variable production costs.

This paper estimates the return on investment in the skeleton weed management program in Western Australia. A bioeconomic model is used to estimate costs to broadacre cropping industries over time with and without the program. Results suggest that without the program annual crop yield losses and increased growing costs, expressed in Australian dollars ($A), could reach A$13.6 million after 30 years. With the program, these losses reduce to A$5.0 million. If annual skeleton weed program costs remain approximately A$3.4 million, the program is likely to produce an annual net benefit to grain producers of A$8.6 million after 30 years.

Background This paper compares the direct benefits to the State of Western Australia from employing a “suppression” policy response to the COVID-19 pandemic rather than a “herd immunity” approach. Methods An S-I-R (susceptible-infectious-resolved) model is used to estimate the likely benefits of a suppression COVID-19 response compared to a herd immunity alternative. Direct impacts of the virus are calculated on the basis of sick leave, hospitalizations, and fatalities, while indirect impacts related to response actions are excluded. Results Preliminary modeling indicates that approximately 1700 vulnerable person deaths are likely to have been prevented over 1 year from adopting a suppression response rather than a herd immunity response, and approximately 4500 hospitalizations. These benefits are valued at around AUD4.7 billion. If a do nothing policy had been adopted, the number of people in need of hospitalization is likely to have overwhelmed the hospital system within 50 days of the virus being introduced. Maximum hospital capacity is unlikely to be reached in either a suppression policy or a herd immunity policy. Conclusion Using early international estimates to represent the negative impact each type of policy response is likely to have on gross state product, results suggest the benefit–cost ratio for the suppression policy is slightly higher than that of the herd immunity policy, but both benefit–cost ratios are less than one.

We live in a world that is increasingly dependent on international trade in a context of substantial regional/national political tensions. Adding to this is an emerging understanding and concern about the social impact of biosecurity and ecosystem services risks associated with such trade. As the key international trade 'arbiter', the World Trade Organisation (WTO) has never before faced such complexity within its decision-making remit. With increasing numbers of bilateral and regional agreements, as well as new developments emerging such as the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP) initiated by multi-national corporations in 2018, the WTO needs to implement ways of reinforcing its legitimacy and enhancing its relevance. This book provides an original analysis of these linked developments and delivers a timely contribution to resolving environment-related international trade disputes. It provides a clear roadmap for improving WTO trade dispute resolution procedures so both biosecurity and ecosystem services risks are considered in evaluating the social, economic and environmental impacts of international trade proposals. In so doing, the WTO should deliver enhanced multilateral social welfare.

Grapevine downy mildew (Plasmopara viticola) was first detected in commercial vineyards in the Swan Valley region of Western Australia (WA) in 1998 and has now spread to all grape-growing regions of the state. This paper uses a bioeconomic model linking weather, spread, infection development, variable production costs and revenue to estimate the costs of P. viticola over time. Results indicate mean annual costs of AUD $7.3 million per year, equivalent to a 1% drop in the gross value of WA grape-growing industries. Cumulative losses since the disease became established are estimated to be AUD $140 million.