Simulation to investigate site-based monitoring of pest insect species for trade

Authors: VAN KLINKEN, REIKS - Commonwealth Scientific And Industrial Research Organisation (CSIRO); GLADISH, DAVID - Commonwealth Scientific And Industrial Research Organisation (CSIRO); Manoukis, Nicholas; CALEY, PETER - Commonwealth Scientific And Industrial Research Organisation (CSIRO); HILL, MATTHEW - Commonwealth Scientific And Industrial Research Organisation (CSIRO)

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/26/2023
Publication Date: 6/14/2023
Citation: van Klinken, R.D., Gladish, D.W., Manoukis, N., Caley, P., Hill, M.P. 2023. Simulation to investigate site-based monitoring of pest insect species for trade. Journal of Economic Entomology. 116(4):1296-1306. https://doi.org/10.1093/jee/toad112.
DOI: https://doi.org/10.1093/jee/toad112

Interpretive Summary: It is difficult to assess where and how many traps to set in an orchard to obtain a given level of confidence that a pest is not present or is below a given low level. In this paper we use a trap model and simulations of insect movement to address this question at the the scale of an individual small orchard. Our approach can be used to quantify relative capture probabilities and may be helpful as a component of a "system approach" relying on low pest prevalence. Our model can be easily extended and applied to other pests, commodities, and environments.

Technical Abstract: Pest insect surveillance using lures is widely used to support market access requirements for traded articles that are hosts or carriers of quarantine pests. Modeling has been used extensively to guide the design of surveillance to support pest free area claims but is less commonly applied to provide confidence in pest freedom or low pest prevalence within sites registered for trade. Site-based surveillance typically needs to detect pests that are already present in the site or that may be entering the site from surrounding areas. We assessed the ability of site-based surveillance strategies to detect pests originating from within or outside the registered site using a probabilistic trapping network simulation model with random-walk insect movement and biologically realistic parameters. For a given release size, time-dependent detection probability was primarily determined by trap density and lure attractiveness, whereas mean step size (daily dispersal) had limited effect. Results were robust to site shape and size. For pests already within the site, detection was most sensitive using regularly spaced traps. Perimeter traps performed best for detecting pests moving into the site, although the importance of trap arrangement decreased with time from release, and random trap placement performed relatively well compared to regularly spaced traps. High detection probabilities were achievable within 7 days using realistic values for lure attractiveness and trap density. These findings, together with the modeling approach, can guide the development of internationally agreed principles for designing site-based surveillance of lure-attractant pests that is calibrated against the risk of non-detection.