Institutional approaches for plant health provision as a collective action problem

Plant biosecurity and One Health: government and industry roles as risk creators and mitigators

The One Health concept highlights the interconnectedness of human, animal, and environmental health and places significant importance on plant biosecurity. This is due to the profound impact of plant biosecurity on food safety and security for animals and people, biodiversity, and the economy. This narrative review examines the roles of government and industry as risk creators and mitigators in plant biosecurity within a One Health framework, focusing on how their collaboration can strengthen surveillance, enhance regulatory policies, and mitigate the spread of plant pests and diseases. Plant biosecurity, which encompasses the measures to safeguard plant biosecurity and life in the same way that animal biosecurity safeguards animal and human health and life, is a critical component of One Health. Measures include a range of policies, regulations, strategies and activities to protect plants from exotic and established pests and diseases. Government, industry, and community actions are critical elements of plant biosecurity. These include pest surveillance and the establishment and maintenance of pest-free areas. Government agencies and industry professionals play a central and pivotal role in shaping plant biosecurity by implementing policies and regulations and developing innovative strategies. These actions can have a dual effect on plant biosecurity: they can either mitigate risks by preventing the introduction and spread of pests or create risks if regulations are inadequate or poorly enforced. The success of plant biosecurity efforts depends on how well government policies align with One Health principles, which require a careful balance between economic, environmental, social and health-related technical/scientific considerations. Pest surveillance, a foundational element of plant biosecurity, provides the tools for early detection and rapid response to pest outbreaks, essential for protecting plant biosecurity. Surveillance programs enable continuous monitoring of pest populations and the detection of emerging threats, which is critical for maintaining pest-free areas. The benefits of pest surveillance are numerous and extend beyond plant biosecurity, contributing to broader One Health objectives by reducing the risk of zoonotic diseases and preserving the ecological integrity of ecosystems. It underpins important economic and trade objectives by projecting confidence in the safety and health of Australia's agricultural products to international trading partners. Strategies to achieve and maintain pest-free areas include stringent quarantine measures, continuous surveillance, and effective rapid response protocols. The interconnectedness of plant biosecurity with One Health is evident in these efforts, as maintaining pest-free areas supports ecosystem health, minimises the need for chemical interventions and consequent pressure on antimicrobial resistance, and promotes sustainable agricultural practices. Government actions, pest surveillance, and the maintenance of pest-free regions are essential components of a robust plant biosecurity strategy. By aligning these measures with One Health principles, it is possible to protect plant biosecurity, enhance environmental sustainability, and contribute to global health outcomes. This holistic approach highlights the importance of cross-sector collaboration and the need for solid biosecurity frameworks to safeguard plant biosecurity in an increasingly interconnected world.

Free-Riding in Plant Health: A Social-Ecological Systems Approach to Collective Action

Plant disease epidemics often transcend land management boundaries, creating a collective-action problem where a group must cooperate in a common effort to maximize individual and group benefits. Drawing upon the social-ecological systems framework and associated design principles, we review variables of resource systems, resource units, actors, and governance systems relevant to collective action in plant health. We identify a need to better characterize how attributes of epidemics determine the usefulness of collective management, what influences actors' decisions to participate, what governance systems fit different plant health threats, and how these subsystems interact to lead to plant health outcomes. We emphasize that there is not a single governance structure that ensures collective action but rather a continuum of structures that depend on the key system variables identified. An integrated social-ecological systems approach to collective action in plant health should enable institutional designs to better fit specific plant health challenges.

Risk-based regionalization approach for area-wide management of HLB vectors in the Mediterranean Basin

Huanglongbing (HLB) is one of the most devastating citrus diseases worldwide. It is associated with the non-culture bacteria Candidatus Liberibacter spp., which can be transmitted by grafting and/or the psyllid vectors Diaphorina citri (ACP) and Trioza erytreae (AfCP). Although HLB has not been reported in the Mediterranean Basin to date, both vectors are present, and thus represent a serious threat to the citrus industry in this region. Resistant citrus cultivars or effective therapeutic treatments are not currently available for HLB. Nevertheless, area-wide pest management via coordinated management efforts over large areas has been implemented in Brazil, China and the USA for HLB control. This study proposes an open access flexible methodology to address area-wide management of both HLB vectors in the Mediterranean Basin. Based on a risk-based approach which considers climatic information and other variables that may influence vector introduction and spread, such as conventional, organic, abandoned and residential citrus areas as well as transportation corridors, an area-wide management division in pest management areas (PMAs) is proposed. The size and location of these PMAs were estimated by means of a hierarchical clustering algorithm with spatial constraints whose performance was assessed under different configuration scenarios. This proposal may assist policymakers and the citrus industry of the citrus-growing areas of the Mediterranean Basin in risk management planning in the case of the spread of HLB vectors or a possible introduction of the disease. Additionally, it may be a valuable resource to inform opinion dynamic models, enabling the identification of pivotal factors for the success of control measures.

Translating virome analyses to support biosecurity, on-farm management, and crop breeding

Virome analysis via high-throughput sequencing (HTS) allows rapid and massive virus identification and diagnoses, expanding our focus from individual samples to the ecological distribution of viruses in agroecological landscapes. Decreases in sequencing costs combined with technological advances, such as automation and robotics, allow for efficient processing and analysis of numerous samples in plant disease clinics, tissue culture laboratories, and breeding programs. There are many opportunities for translating virome analysis to support plant health. For example, virome analysis can be employed in the development of biosecurity strategies and policies, including the implementation of virome risk assessments to support regulation and reduce the movement of infected plant material. A challenge is to identify which new viruses discovered through HTS require regulation and which can be allowed to move in germplasm and trade. On-farm management strategies can incorporate information from high-throughput surveillance, monitoring for new and known viruses across scales, to rapidly identify important agricultural viruses and understand their abundance and spread. Virome indexing programs can be used to generate clean germplasm and seed, crucial for the maintenance of seed system production and health, particularly in vegetatively propagated crops such as roots, tubers, and bananas. Virome analysis in breeding programs can provide insight into virus expression levels by generating relative abundance data, aiding in breeding cultivars resistant, or at least tolerant, to viruses. The integration of network analysis and machine learning techniques can facilitate designing and implementing management strategies, using novel forms of information to provide a scalable, replicable, and practical approach to developing management strategies for viromes. In the long run, these management strategies will be designed by generating sequence databases and building on the foundation of pre-existing knowledge about virus taxonomy, distribution, and host range. In conclusion, virome analysis will support the early adoption and implementation of integrated control strategies, impacting global markets, reducing the risk of introducing novel viruses, and limiting virus spread. The effective translation of virome analysis depends on capacity building to make benefits available globally.

Climate Change Effects on Pathogen Emergence: Artificial Intelligence to Translate Big Data for Mitigation

Plant pathology has developed a wide range of concepts and tools for improving plant disease management, including models for understanding and responding to new risks from climate change. Most of these tools can be improved using new advances in artificial intelligence (AI), such as machine learning to integrate massive data sets in predictive models. There is the potential to develop automated analyses of risk that alert decision-makers, from farm managers to national plant protection organizations, to the likely need for action and provide decision support for targeting responses. We review machine-learning applications in plant pathology and synthesize ideas for the next steps to make the most of these tools in digital agriculture. Global projects, such as the proposed global surveillance system for plant disease, will be strengthened by the integration of the wide range of new data, including data from tools like remote sensors, that are used to evaluate the risk ofplant disease. There is exciting potential for the use of AI to strengthen global capacity building as well, from image analysis for disease diagnostics and associated management recommendations on farmers' phones to future training methodologies for plant pathologists that are customized in real-time for management needs in response to the current risks. International cooperation in integrating data and models will help develop the most effective responses to new challenges from climate change.

Sustainable management of transboundary pests requires holistic and inclusive solutions

Globalization and changing climates are aggravating the occurrence and impacts of transboundary pests, and driving the emergence of new threats. Most of the low- and middle-income countries in Africa, Asia and Latin America are not fully prepared in terms of surveillance, diagnostics, and deployment of plant health solutions due to several factors: adequate investment is lacking; knowledge is inadequate; and connections from the local to global, and global to local are insufficient. Effectively countering the current and emerging threats to plant health requires a holistic approach that includes: 1) globally coordinated diagnostic and surveillance systems; 2) epidemiological modelling, risk assessment, forecasting and preparedness for proactive management and containment; and 3) implementation of context-sensitive, eco-friendly, gender-responsive and socially inclusive integrated disease and pest management approaches to reduce the impacts of devastating transboundary pests and diseases. Despite several success stories where major pests and diseases have been brought to control through integrated approaches, further multi-institutional and multi-disciplinary efforts are necessary. Plant health management requires stronger interface between the biophysical and social sciences, and empowerment of local communities. These reflections derive from the proceedings of a webinar on “Transboundary Disease and Pest Management,” organized by CGIAR (Consultative Group on International Agricultural Research) on March 3, 2021, in recognition of the United Nations designated International Year of Plant Health.

Cultural Management of Huanglongbing: Current Status and Ongoing Research

Huanglongbing (HLB), formerly known as greening, is a bacterial disease restricted to some Asian and African regions until two decades ago. Nowadays, associated bacteria and their vectors have spread to almost all citrus-producing regions, and it is currently considered the most devastating citrus disease. HLB management can be approached in terms of prevention, limiting or avoiding pathogen and associated vectors to reach an area, or in terms of control, trying to reduce the impact of the disease by adopting different cultural strategies depending on infestation/infection levels. In both cases, control of psyllid populations is currently the best way to stop HLB spread. Best cultural actions (CHMAs, TPS system) to attain this goal and, thus, able to limit HLB spread, and ongoing research in this regard is summarized in this review.