This was presented by Angela Fuller as a part of a series of contributed talks from the 2022 FEMC Annual Conference. To learn more about the conference, visit: https://www.uvm.edu/femc/cooperative/conference/2022
Invasive species have the potential to decrease productivity of crop systems, forests, fisheries, and waterways resulting in negative ecological, economic, and societal impacts in the US and worldwide. Prevention and early detection of invasive species are championed as the most cost-effective and efficient strategies for reducing or avoiding these negative impacts on systems. Spotted lanternfly (SLF), Lycorma delicatula, is a recently introduced invasive insect that has been expanding rapidly and causing severe impacts to agricultural production, particularly grapes, since it was first discovered in Pennsylvania in 2014. Human visual surveys are the most common search method employed but can be ineffective due to the insect's cryptic egg masses and low density during early stages of infestation. Therefore, finding alternative SLF early detection methods has become a priority for agencies tasked with addressing SLF management and use of detection dogs has been increasingly considered for this purpose. This study served to test experimentally whether utilizing detector dogs could improve the likelihood of detecting SLF in both agricultural and natural settings. We surveyed transects in 20 vineyards in PA and NJ and used a multi-scale occupancy model to estimate detection probability of human observers and trained detection dogs as a function of SLF infestation level and weather covariates. We hypothesized that 1) occupancy rates vary across sites as a function of the overall SLF infestation level at a site and 2) human and dog detection probability is higher at sites with higher infestation levels because there should be more SLF eggs available for detection. We modeled transect-level occupancy of SLF as a function of infestation level, habitat, topographic position index, and distance to forest. We found that occupancy probability of SLF was higher on vines within the vineyards compared with in the forest and was higher at high infestation sites compared to low infestation sites. Occupancy probability declined with increasing distance from forest which is informative for future search efforts. Detection probability of SLF was lower in forested sites and was higher at high infestation sites. Detection dogs had a lower detection probability than humans in the vineyard, but a higher detection probability than humans in forested sites. The higher detection probability of detection dogs in forested sites was offset by longer dog search time compared with humans. Our study suggests that detection dogs could be more effective than human visual searches as an early detection method for SLF in natural areas and utilizing detector dogs could strengthen SLF early detection efforts.