Risk Based Surveys

Risk-based survey design

In the ongoing battle against the spread of citrus diseases such as Huanglongbing (HLB), innovative strategies and collaborative efforts are paramount. Our Risk-based Survey (RBS) design represents a cutting-edge approach to early detection and prediction of Asian Citrus Psyllid (ACP) and HLB in both residential and commercial citrus orchards across California. By utilizing the power of risk mapping and predictive modeling, we are setting new standards for the efficient and proactive management of these devastating diseases.

Our work, developed in close collaboration with the California Department of Food and Agriculture (CDFA), the Citrus Research Board (CRB), and the Citrus Pest & Disease Prevention Committee (CPDPC), focuses on identifying and locating CLas-infected trees at the earliest possible stage. This early detection capability is crucial for implementing timely and effective management interventions that can prevent the widespread establishment and rapid spread of HLB. Utilizing sophisticated model predictions and risk maps, our team is able to guide the strategic deployment of resources, ensuring that survey and surveillance efforts are concentrated in areas where the risk of disease transmission is highest.

The cornerstone of our approach is the creation of dynamic, accurate risk maps that visualize the major risk factors affecting citrus orchards across California (Figure 1). These maps, updated regularly to reflect the evolving nature of the epidemic, incorporate a wide range of risk factors, from the spatiotemporal analysis of ACP distribution to the assessment of risks associated with citrus transportation networks and proximity to military installations. By providing a comprehensive overview of potential threats, our risk maps enable surveyors to target their efforts more effectively, greatly enhancing the chances of early HLB detection.

 

Figure 1: Major risk factors for statewide residential and commercial surveillance in Southern California. Hotter colors (e.g., red) indicate high risk, while colder colors (blue) indicate low risk.

Our rigorous, data-driven approach also involves a retrospective longitudinal analysis to assess the predictive power of each risk factor over time. This continuous evaluation and refinement of our models ensure their accuracy and relevance, enabling us to adjust our strategies in response to changes in the epidemic’s dynamics. The result is a highly efficient, resource-optimized survey design that maximizes our ability to protect California’s citrus industry from the devastating impacts of ACP and HLB.

The success of our RBS survey design work underscores the importance of innovation, collaboration, and adaptability in the fight against citrus diseases. As we continue to refine our models and strategies, we remain committed to safeguarding the health of citrus orchards across California, ensuring the long-term viability and prosperity of the industry. Through our efforts, we not only aim to combat the current HLB epidemic but also to set a new standard for disease management in agriculture, demonstrating the power of science and collaboration in addressing complex agricultural challenges.

  • Luo. W., Posny. D. & McRoberts. N. (2024) A smarter way to survey for HLB – Evaluating a risk-based model in Southern California. To be appeared in Citrograph Spring 2024
  • Galvan, A., Bassanezi, R., Luo., W., Vanaclocha, P., Vicent, A., & Lazaro, E. (2023) Risk-based regionalization approach for area-wide management of HLB vectors in the Mediterranean Basin. Front Plant Sci. 2023 Dec 4;14:1256935. doi: 10.3389/fpls.2023.1256935.
  • Gottwald, T., Luo, W., Posny, D., Riley, T., Louws, F. (2019) A probabilistic census travel model to predict introduction sites of exotic plant, animal and human pathogens. Phil. Trans. R. Soc. B 20180260. http://dx.doi.org/10.1098/rstb.2018.0260
  • Gottwald, T. R., Luo, W., and McRoberts, N. (2013) Risk-Based Residential HLB/ACP Survey for California, Texas, and Arizona. Plant Management Network. http://www.plantmanagementnetwork.org/edcenter/seminars/Outreach/Citrus/HLB/